# The 9th International Workshop on Charm Physics (CHARM18)

Asia/Novosibirsk
Budker INP

#### Budker INP

Lavrentiev av. 11, Novosibirsk 630090
Description

The 9th International Workshop on Charm Physics (CHARM 2018) will be held at Budker Institute of Nuclear Physics, Novosibirsk, Russia on May 21-25, 2018.

The purpose of CHARM 2018 Workshop is to bring together particle and nuclear physicists working in the field related to physics of charm quark to discuss recent results in the field, including the impact on and from theory, as well as projections for results to be expected from upcoming facilities.

Workshop topics:

• Charm and Exotics
• Charm Meson and Baryon Spectroscopy
• Production of Charm and Charmonia
• Hidden and Open Charm in Media
• Light Hadronic Spectroscopy from Decays of Charm and Charmonia
• Leptonic, Semileptonic, Radiative and Rare Charm Decays
• D Oscillations and CP Violation
• Tau lepton physics
• New Physics Scenarios for Charm Decays
• Experimental Charm Facilities - Status and Future

May, 10th. Please find the Second Conference Bulletin.

Conference Website - here

Conference co-hosted by
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Participants
• Alberto Lusiani
• Alessandro Grelli
• Alessandro Miccoli
• ALESSANRO DI CICCO
• Alexander Barnyakov
• Alexander Popov
• Alexei Garmash
• Alexey Dzyuba
• Alexey Nefediev
• Alexey Onuchin
• Anatoly Vorobiov
• Andrea Contu
• Andrey A. Prokopenko
• Andrey Sokolov
• Angelo Carbone
• Anna Loiseau
• Anna Vinokurova
• Anthony Francis
• Anton Poluektov
• Antonio D Polosa
• Antonio Pich
• Avetik Hayrapetyan
• Baoyi Chen
• Benoit Loiseau
• Biaogang Wu
• Bingsong Zou
• Boris Shwartz
• Bostjan Golob
• Changzheng YUAN
• Clarissa Azevedo Baesso
• Daniel Evangelho Vieira
• Daniel Greenwald
• Darren Price
• Denis Epifanov
• Dmitrii Dementev
• Dmitriy Berkaev
• Dmitry Dedovich
• Dmitry Matvienko
• Dmytro Levit
• Dominik Stefan Mitzel
• Elisabetta Prencipe
• Eugeniy Solodov
• Evgeny Kozyrev
• Feng-Kun Guo
• Francesca Curciarello
• Francesco Grancagnolo
• Francesco Knechtli
• Fu-Sheng Yu
• Galina Pakhlova
• Giorgio Salerno
• Giovanni Bencivenni
• Giulia Casarosa
• Gongming Yu
• Guangshun Huang
• Hai-Bo Li
• Hai-Tao Shu
• Haiping Peng
• Hajime Muramatsu
• Hong-Fei Zhang
• Igor Denisenko
• Ivan Belyaev
• James Lambrecht Ritman
• Jaume Tarrus Castella
• Jiaxing Zhao
• Jochen Schwiening
• Johan Messchendorp
• Jorgivan Morais Dias
• Kirill Chilikin
• Korneliy Todyshev
• Leonid Epshteyn
• Li Ma
• Lucie Linssen
• Maksim Kuzin
• Manfred Berger
• Marianna Mazzilli
• Masayuki Niiyama
• Matteo Fael
• Maxime Schubiger
• Menglin Du
• Michael Sokoloff
• Miguel Ángel Escobedo Espinosa
• Mikhail Barabanov
• Mikhail Mikhasenko
• Nikolay Gabyshev
• Nilmani Mathur
• Olga Gzhymkovska
• Pablo Roig Garces
• Patrick Robbe
• Pavel Piminov
• Peter Lukin
• Qin Qin
• Randy Lewis
• Riccardo Farinelli
• Ryan Mitchell
• Semen Turchikhin
• Sergei Gribanov
• Sergey Barsuk
• Sergey Kononov
• Sergey Serednyakov
• Shuangshi Fang
• Simon Eidelman
• Stanislav Poslavsky
• Stefan Ropertz
• Stephen Lars Olsen
• Syaefudin Jaelani
• Tagir Aushev
• Tatyana Kharlamova
• Tim Evans
• Timofey Uglov
• Tomasz Skwarnicki
• Tung Meng Fung
• Valentina Zhukova
• Valery Tayursky
• Vasily Shebalin
• Vitaly Vorobyev
• Xiao-Yu Guo
• Xiaolong Wang
• XIAOMING ZHANG
• Xiaorui Lyu
• Xiaoyan Shen
• Xiongfei Wang
• Yan-Qing Ma
• Yeqi Chen
• Yu Zhang
• Yuping Guo
• Yury Kudenko
• Yury Malakhov
• Zalak Shah
• Zbigniew Was
• Zebo Tang
• ZHENGGUO ZHAO
Support
• Monday, 21 May
• 08:00 09:00
Registration 1h
• 09:00 09:15
Welcome by Prof. Pavel Logachev 15m
• 09:15 10:45
Charm Facilities
Convener: Prof. Zhengguo ZHAO (University of Science and Technology of China)
• 09:15
A project of Super-charm-tau Factory in Novosibirsk 30m
Speaker: Prof. Eugeny Levichev (BINP)
• 09:45
Prospects of Charm Physics with Belle II 30m
Speaker: Dr Giulia Casarosa (INFN Sezione di Pisa)
• 10:15
LHCb upgrade and prospects of Charm Physics 30m
Speaker: Dr Alexey Dzyuba (B.P. Konstantinov Petersburg Nuclear Physics Institute National Research Center "Kurchatov Institute")
• 10:45 11:15
Coffee Break 30m
• 11:15 12:45
Charm Facilities
Convener: Prof. Eugeny Levichev (BINP)
• 11:15
HIEPA - Super-tau-charm Factory in China 30m
Speaker: Dr Haiping Peng (USTC)
• 11:45
Prospects of Charm Physics at PANDA 30m
The ambition of the antiProton ANnihilation at DArmstadt (PANDA) collaboration is to address various questions related to the strong interactions by employing a multi-purpose detector system at the near-future Facility for Antiproton and Ion Research (FAIR). The usage of antiprotons with unprecedented momentum resolution and intensity will give access to a unique physics program. With center-of-mass energies up to 5.5~GeV, PANDA will be able to probe various aspects of QCD from light to charm-like systems. In this presentation, I will give an overview and motivation of the overall physics program of PANDA at FAIR with emphasis on the prospects of studying hidden- and open-charm(like) hadrons in the first phase of data taking.
Speaker: Dr Johan Messchendorp (KVI-CART)
• 12:15
Prospects of Charm Physics at ATLAS 30m
Speaker: Dr Semen Turchikhin (Joint Institute for Nuclear Research)
• 12:45 13:00
Group photo (main entrance) 15m
• 13:00 14:30
Lunch 1h 30m
• 14:30 16:00
Exotics
Convener: Prof. Tomasz Skwarnicki (Syracuse University)
• 14:30
Charm and exotic hadrons from B factories 30m
Speaker: Prof. Stephen Olsen (UCAS)
• 15:00
Charm and exotic hadrons from BES III 30m
The recent results on the study of the charmoniumlike states at the BESIII experiment will be presented, including the cross sections of e+e- to pi+pi-J/psi, pi+pi-hc, pi+pi-psi', pi+pi-psi'', pi+pi-pi0eta_c, K+K-J/psi and the intermediate states in these modes, the cross sections of e+e- to eta J/psi, eta' J/psi, eta hc, phi chi_c, gamma eta_c, gamma X(3872), and so on. Perspectives of the studies of exotics at BESIII will also be shown.
Speaker: Prof. Changzheng Yuan (IHEP, Beijing)
• 15:30
Charm and exotic hadrons from LHCb 30m
Speaker: Dr Anton Poluektov (University of Warwick)
• 16:00 16:30
Coffee Break 30m
• 16:30 19:00
Exotics
Convener: Prof. Galina Pakhlova (MIPT)
• 16:30
Complementarity of beauty and charm hadron physics 30m
Speaker: Prof. Alex Bondar (BINP)
• 17:00
XYZ states as compact tetraquarks 30m
Speaker: Prof. Antonio Davide Polosa (Sapienza University of Rome)
• 17:30
XYZ at Belle II 25m
Speaker: Dr Elisabetta Prencipe (Forschungszentrum Juelich - IKP1)
• 17:55
XYZ at the upgraded LHCb 25m
Speaker: Prof. Tomasz Skwarnicki (Syracuse University)
• 18:20
XYZ states as hadronic molecules 30m
In the past decade, a lot of new hadrons containing heavy quarks were discovered which do not fit into the scheme provided by the traditional quark models. Such states are known as the XYZ states and they are traditionally referred to as exotic ones. At present, there is no consensus on their nature, and different models and approaches have been suggested to explain their unusual properties. The talk is devoted to a brief overview of the molecule model for such exotic states.
Speaker: Dr Alexey Nefediev (Lebedev Physical Institute)
• 19:00 21:00
Welcome reception (BINP Cafeteria) 2h
• Tuesday, 22 May
• 09:00 10:30
Exotics
Convener: Prof. Feng-Kun Guo (Institute of Theoretical Physics, Chinese Academy of Sciences)
• 09:00
Charmonium and exotics from lattice QCD 30m
We review selected lattice results on the charmonium spectrum and first attempts to search for the existence of exotic states. The hadro-quarkonium model was proposed to interpret some of the exotic states as a quarkonium core inside a hadron. We present a lattice study of the hadro-quarkonium model in the limit of static quarks. The charm quark decouples in low energy observables and binding energies of charmonium. In a model calculation we are able to evaluate the corrections to decoupling of the charm quark in the continuum.
Speaker: Prof. Francesco Knechtli (University of Wuppertal)
• 09:30
Heavy hybrids and tetraquarks in EFT 30m
In the past decade a large amount of unexpected states have been discovered in the charmonium and bottomonium spectra. These states are candidates for nontraditional hadronic states including four quarks or gluonic excitations as constituents. Many of these states can be identified as heavy quark-antiquark bound states in gluonic and light-quark static energies. In this talk I elaborate on an effective field theory approach that takes inspiration from the Born-Oppenheimer approximation that can be used to describe these exotic states with input from lattice QCD. Results for the hybrid spectrum including spin-dependent contributions and semi-incusive decays into quarkonia will be reviewed.
Speaker: Dr Jaume Tarrus Castella (IFAE)
• 10:00
Penta-quarks with hidden charm and their strange beauty partners 30m
I will introduce some interesting progress on Penta-quarks with hidden charm and their strange beauty partners
Speaker: Prof. Bingsong Zou (Institute of Theoretical Physics, CAS)
• 10:30 11:00
Charmed Meson and Baryon Spectroscopy
Convener: Galina Pakhlova (MIPT)
• 10:30
Experimental Status of Conventional Charmonium Spectroscopy 30m
In this talk, I will present most recent experimental status on conventional charmonium spectroscopy based on the data collected from the BESIII, Belle, LHCb and KEDR Collaborations. These include improved measurements of two-photon widths of $\chi_{c J}$ states and helicity analysis $\chi_{c 2} \to \gamma \gamma$, $\chi_{c 1,2}$ resonance parameters with the decays $\chi_{c 1,2} \to J/\psi \mu^+ \mu^-$, and $\eta_c$ resonance parameters measurement, the $J/\psi$ decay widths measurement, determination of $J/\psi$ and $\psi(2S)$ masses, observations of $X(3823)$ and $X(3860)$.
Speaker: Dr Xiongfei Wang (Institute of High Energy Physics)
• 11:00 11:30
Coffee Break 30m
• 11:30 13:00
Charmed Meson and Baryon Spectroscopy
Convener: Prof. Galina Pakhlova (MIPT)
• 11:30
Charmed hadron spectroscopy at Belle 30m
Using the 980 fb${}^{-1}$ full data sample taken with the Belle detector, there are measurements finished recently. Studies of charmed hadron spectroscopy, especially the baryons, from Belle experiment are presented. A strange pentaquark state has been searched for in $\Lambda_C \to \pi^0 p \Phi$. Branching fraction of hadron decays of $\Omega_c$ have been measured. There is observation of $\Xi_c(2930)$ in $\Lambda^+ K^-$ final states. Belle confirmed the excited $\Omega_c$ states observed by LHCb. Production rates of various baryons is also studied.
Speaker: Prof. Xiaolong Wang (Fudan University)
• 12:00
Doubly-charmed baryons at LHCb 30m
The first observation of the doubly charmed baryon was reported by LHCb collaboration in 2017. The ongoing studies of the $\Xi_{cc}$ properties within the LHCb collaboration are presented.
Speaker: Dr Daniel Evangelho Vieira (University of Chinese Academy of sciences)
• 12:30
Status of Charmed Meson Spectroscopy 30m
In this talk, I will review the status of charmed meson spectroscopy, paying particular attention to the recent progress made using effective field theories and lattice QCD.
Speaker: Prof. Feng-Kun Guo (Institute of Theoretical Physics, Chinese Academy of Sciences)
• 13:00 14:30
Lunch 1h 30m
• 14:30 16:00
Charmed Meson and Baryon Spectroscopy
Convener: Prof. Ryan Mitchell (Indiana University)
• 14:30
Charmed Hadron Spectroscopy at LHCb 30m
Speaker: Dr Patrick Spradlin (University of Glasgow)
• 15:00
Theoretical Aspects of Charmed Baryons 30m
The study of heavy hadrons is passing through an incredible era with the discovery of numerous heavy subatomic particles. The study of charm baryons is an integral part of this resurgence in scientific interest to explore the spectrum of strongly interacting heavy hadrons. I will present theoretical aspects of charmed baryons with emphasis on results from lattice calculations.
Speaker: Prof. Nilmani Mathur (Tata Institute of Fundamental Research)
• 15:30
Open bottom tetraquarks and their relation to doubly charmed baryons 30m
Speaker: Dr Randy Lewis (York University)
• 16:00 16:30
Coffee Break 30m
• 16:30 17:20
Charmed Meson and Baryon Spectroscopy
Convener: Prof. Boris Shwartz (Budker Institute of Nuclear physics)
• 16:30
Lambda_c Physics at BESIII 30m
Speaker: Dr Xiaorui Lyu (University of Chinese Academy of Sciences (UCAS), Beijing)
• 17:00
Charmonium at KEDR 20m
We report new precise results of experiments performed with the KEDR detector at the VEPP-4M e+e- collider. They include final results for J/ψ and ψ(2S) parameters and R measurement. Cross sections for the processes e+e- →hadrons and e+e- → e+e- were measured at J/ψ resonance energy range and leptonic width of J/ψ meson and its composition to hadronic and electronic branching fractions were obtained with accuracy less than 2%. The product of the electronic width of the ψ(2S) meson and the branching fraction of its decay to the muon pair was measured in the e+e−→ψ(2S)→μ+μ− process with the world best accuracy about 3%. Leptonic width of ψ(2S) meson was calculated, using the previous KEDR measurements with the lepton universality assumption and without it. Recently the R was measured in the center-of-mass energy between 3.0 and 3.8 GeV with the total accuracy up to 2.6%.
Speaker: Mrs Tatyana Kharlamova (BINP, NSU)
• 17:20 18:20
Excursion over BINP 1h
• Wednesday, 23 May
• 09:00 11:00
Production of Charm and Charmonia
Convener: Prof. Yan-Qing Ma (Peking University)
• 09:00
Open charm production at LHC 30m
Speaker: Dr Sergey Barsuk (LAL)
• 09:30
Review of Heavy Quarkonium Production 30m
Many important progresses in heavy quarkonium physics have been made in recent years. This talk wants to provide a state-of-the-art introduction to both the theoretical and phenomenological progresses in heavy quarkonium production, including the newly proposed Soft Gluon Factorization (SGF), and Improved Color Evaporation Model (ICEM), and the phenomenological studies in NRQCD.
Speaker: Dr Hong-Fei Zhang (TBD)
• 10:00
Charmonium production at LHC (prompt and from B decays) 30m
Speaker: Dr Xiaorui Lyu (University of Chinese Academy of Sciences (UCAS), Beijing)
• 10:30
Double charmonia production in the LHC 30m
In this talk I'll give a brief overview of the recent theoretical results on paired charmonia production in the LHC. Special attention will be payed to the problem of parton shower formation, namely to the problem how one can discriminate between single parton scattering and double parton scattering, and how these different mechanisms manifests in the picture of multiple heavy quarkonia production.
Speaker: Dr Stanislav Poslavsky (Institute for High Energy Physics NRC "Kurchatov Institute")
• 11:00 11:30
Coffee Break 30m
• 11:30 12:30
Production of Charm and Charmonia
Convener: Dr Ivan Belyaev (CERN/Geneva & ITEP/Moscow)
• 11:30
Multiple charm(onium) production at LHC 30m
Speaker: Dr Semen Turchikhin (Joint Institute for Nuclear Research)
• 12:00
Soft gluon factorization 30m
Speaker: Prof. Yan-Qing Ma (Peking University)
• 12:30 13:00
Hidden and Open Charm in Media
Convener: Prof. Ivan Belyaev (CERN/Geneva & ITEP/Moscow)
• 12:30
Experimental review of Open Charm in pA collisions 30m
Speaker: Dr Alessandro Grelli (Utrecht University)
• 13:00 14:30
Lunch 1h 30m
• 14:30 16:30
Parallel Session I
Convener: Dr Alexey Nefediev (Lebedev Physical Institute)
• 14:30
Disclosing $D^{*}\bar{D}^{*}$ molecular states in the $B_c^-\to \pi^- J/\psi\omega$ decay 17m
In this work, we have studied the $B_c^-\to \pi^- J/\psi\omega$ and $B_c^-\to \pi^- D^{*}\bar{D}^{*}$ reactions. In particular, we have shown they are related by the presence of two resonances: the $X(3940)$ and $X(3930)$, which are of molecular nature and couple mostly to $D^{*}\bar{D}^{*}$, but also to $J/\psi\omega$. Because of that, in the $J/\psi\omega$ mass distribution we find a cusp with large strength at the $D^{*}\bar{D}^{*}$ threshold and predict the ratio of strengths between the peak of the cusp and the maximum of the $D^{*}\bar{D}^{*}$ distribution close to $D^{*}\bar{D}^{*}$ threshold, which are distinct features of the molecular nature of these two resonances.
Speaker: Dr Jorgivan Morais Dias (Institute of Physics, University of São Paulo, Brazil)
• 14:47
Study of charmoniumlike states by amplitude analyses at Belle 17m
A review of charmoniumlike state studies by means of amplitude analyses at Belle is presented, including the analyses of $\bar{B}^0 \rightarrow \psi(2S) \pi^+ K^-$, $\bar{B}^0 \rightarrow J/\psi \pi^+ K^-$. The analysis of $e^+ e^- \to J/\psi D \bar{D}$ is discussed in more detail. Prospects of similar analyses at Belle II are mentioned.
Speaker: Dr Kirill Chilikin (LPI RAS)
• 15:04
Angular analysis of the $e^{+}e^{-} \to D^{(*)}D^{*}$ process near the open-charm threshold using initial-state radiation 17m
New results are obtained for the exclusive cross sections of the $e^+e^-$ annihilation into charmed hadron pairs with initial state radiation. The analysis is based on the data sample collected with the Belle detector with the integrated luminosity of 951 fb${}^{-1}$. The accuracy of the cross section measurement is increased by a factor of 2 compared with the previous Belle study and, for the first time, the $e^+ e^- \to D^{\ast}D^{\ast}$ cross section is decomposed into three components corresponding to different helicities of the $D^{*}$'s in the final state.
Speaker: Ms Valentina Zhukova (LPI)
• 15:21
Exclusive open-charm near-threshold cross sections in a coupled-channel approach 17m
Data on 7 open-charm channels collected by the Belle Collaboration are analyzed simultaneously using a unitary approach based on a coupled-channel model in a wide energy range $\sqrt{s}=$3.7-4.7~GeV. The resulting fit provides a remarkably good overall description of the line shapes in all studied channels. Parameters of 5 vector charmonium resonances are extracted from the fit. It is demonstrated, that this approach could be used account for all exclusive channels and thus solve the long-term problem of the charmonium spectra near threshold. The talk is based on "Exclusive open-charm near-threshold cross sections in a coupled-channel approach" by T. Uglov et all JETP Lett. 105 (2017) no.1, 1.
Speaker: Dr Timofey Uglov (LPI RAS)
• 15:38
Properties of $Z_b(10610)$ and $Z_b(10650)$ from an analysis of experimental line shapes 17m
The experimental line shapes available in the $B\bar{B^{\ast}}$, $B^{*}\bar{B^{\ast}}$, $h_b(1P)\pi$ and $h_b(2P)\pi$ channels are analysed using a theoretical EFT-based framework manifestly consistent with unitarity and analyticity. The line shapes are calculated using a system of coupled channel integral equations with the potential consisting of the one-pion and one-eta meson exchange interactions from the lightest Goldstone boson octet as well as of several contact terms at leading and subleading orders which are adjusted to minimise the overall chi squared. The pole positions of the $Z_b(10610)$ and $Z_b(10650)$ are extracted for the best fits corresponding to chi squared of the order of one. The role of the long and intermediate range pion and eta dynamics, as well as of the effects violating heavy quark spin symmetry, is discussed. Insights for the corresponding charmonium-like states $Z_c$’s are considered.
Speaker: Dr Vadim Baru (HISKP, Bonn University)
• 15:55
Lattice Predictions for Bound Heavy Tetraquarks 17m
We investigate the possibility of $qq^\prime \bar Q \bar Q^\prime$ tetraquark bound states using $n_f=2+1$ lattice QCD with pion masses $\simeq 164$, $299$ and $415$ MeV. Two types of lattice interpolating operator are chosen, reflecting first diquark-antidiquark and second meson-meson structure. Performing variational analysis using these operators and their mixings, we determine the ground and first excited states from the lattice correlators. Using non-relativistic QCD to simulate the bottom quarks and the Tsukuba formulation of relativistic heavy quarks for charm quarks, we study the $ud\bar b \bar b$, $\ell s\bar b \bar b$ as well as $ud\bar c \bar b$, channels with $\ell=u,d$. In the case of the $ud\bar b \bar b$ and $\ell s\bar b \bar b$ channels unambiguous signals for $J^P=1^+$ tetraquarks are found with binding energies $189(10)$ and $98(7)$ MeV below the corresponding free two-meson thresholds at the physical point. These tetraquarks are therefore strong-interaction stable, implying they are stable under strong as well as electromagnetic interactions while they can decay weakly. So far these are the first exotic hadrons predicted to have this feature. Further evidence for binding is found in the $ud\bar c \bar b$ channel, whereby the binding energy broadly straddles the electromagnetic stability threshold. Studying further the quark mass dependence we vary the heavy quark mass in $ud\bar Q \bar Q$, $\ell s\bar Q \bar Q$ as well as $ud\bar Q \bar b$, $\ell s\bar Q \bar b$ between roughly 0.7 and 6.3 times the bottom quark mass. The observed mass dependence of these four flavor channels closely follows a behaviour argued from phenomenological considerations of the heavy quark potential.
Speaker: Dr Anthony Francis (CERN)
• 16:12
Pole position of the $a_1(1260)$ in the $\tau$ decay 17m
The discrepancy between different determinations of mass and width of the ground axial-vector state $a_1(1260)$ is a long-standing issue. Measurements include the resonance production in hadronic processes, i.e. central production, antiproton-proton annihilation, and diffraction experiments, with COMPASS providing the most accurate determination of Breit-Wigner parameters so far. On the other end, the cleanest source of the hadron axial sector $J^{PC} = 1^{++}$ is leptoproduction in the reaction $\tau\to3\pi\,\nu_\tau$ where the most precise data were collected by CLEO and ALEPH experiments. In order to establish an agreement, we analyze the data using analyticity and unitarity constraints and characterize the resonance by its pole position. In this talk, we report on an analysis of the $3\pi$ spectrum from $\tau$ decays measured by the ALEPH experiment. We also accomplished the analytical continuation of the spectral function, which is a delicate procedure as it deals with the three-body final state. I will present the results for the $a_1(1260)$ resonance pole position extracted for the first time and discuss systematic uncertainties.
Speaker: Dr Mikhail Mikhasenko (HISKP, Universität Bonn)
• 14:30 16:30
Parallel Session II
Convener: Prof. Tomasz Skwarnicki (Syracuse University)
• 14:30
Direct production of chi_c1 at the e+e- collider BES III 17m
Up to now, only resonances with $J^{PC}=1^{--}$ have been observed in electron-positron annihilation, while $C=+1$ resonances appear only among the decay products. The direct production of $1^{++}$ states could happen through two virtual photon. Due to the smallness, this process has never been verified experimentally. Given the high luminosity  at the BESIII experiment, a search of direct production of $\chi_{c1}$ is undergoing with dedicated data samples around the $\chi_{c1}$ mass region. We will present an overview of the data analysis.
Speaker: Dr Yuping Guo (Institut für Kernphysik,Johannes Gutenberg-Universität Mainz)
• 14:47
Measurement of the $D^{*+} - D^+$ mass difference 17m
We measure the mass difference, $\Delta m_+$, between the $D^{*}(2010)^+$ and the $D^+$, using the decay chain $D^{*}(2010)^+ \to D^+ \pi^0$ with $D^+ \to K^- \pi^+ \pi^+$. The data were recorded with the BaBar detector at center-of-mass energies at and near the $\Upsilon(4S)$ resonance, and correspond to an integrated luminosity of approximately $468 \, \mbox{fb}^{-1}$. We measure $\Delta m_+ = \left(140\,601.0 \pm 6.8\,[{\rm stat}] \pm 12.9 \,[{\rm syst}]\right) \, \mbox{keV}$. We combine this result with a previous BaBar measurement of $\Delta m_0\equiv m(D^{*}(2010)^+) - m (D^0)$ to obtain $\Delta m_D = m(D^+) - m(D^0) = \left(4\,824.9 \pm 6.8\,[{\rm stat}] \pm12.9\,[{\rm syst}]\right) \, \mbox{keV}$. These results are compatible with, and approximately five times more precise than, previous Particle Data Group averages.
Speaker: Prof. Michael Sokoloff (University of Cincinnati)
• 15:04
Double heavy tri-hadron bound state via delocalized $\pi$ bond 17m
The number of exotic candidates which are beyond the conventional quark model has grown dramatically during the last decades. Some of them could be viewed as analogues of the deuteron. Similarly, the existence of the triton indicates that bound states formed by three hadrons could also exist. To illustrate this possibility, we study the $DD^{\ast}K$ and $BB^{\ast}\bar{K}$ systems by using the Born-Oppenheimer Approximation. To leading order, only one-pion exchange potentials are considered, which means that the three constitutes share one virtual pion. That is similar to the role of the delocalized $\pi$ bond for the formation of Benzene in chemistry. After solving the Schr\"odinger equation, we find two three-body $DD^{\ast}K$ and $BB^{\ast}\bar{K}$ bound states with masses $4317.92_{-4.32}^{+3.66}~\mathrm{MeV}$ and $11013.65_{-8.84}^{+8.49}~\mathrm{MeV}$, respectively. The masses of their $D\bar{D}^{\ast}K$ and $B\bar{B}^{\ast}\bar{K}$ analogues are $4317.92_{-6.55}^{+6.13}~\mathrm{MeV}$ and $11013.65_{-9.02}^{+8.68}~\mathrm{MeV}$. From the experimental side, the $D\bar{D}^{\ast}K$ bound state could be found by analyzing the current world data of the $B\to J/\psi\pi\pi K$ process by focusing on the $J/\psi \pi K$ channel. Its confirmation could also help to understand the formation of kaonic nuclei in nuclear physics.
Speaker: Dr Li Ma (Helmholtz-Institut für Strahlen- und Kernphysik, Universität Bonn)
• 15:21
Mass spectra of triply heavy charm-beauty baryons 17m
We extract the mass spectra of triply heavy charm-beauty baryons using Hypercentral constituent quark model. The first order correction is also added to the potential term of Hamiltonian. The radial and orbital excited state masses are also determined. Moreover, the Regge trajectories and magnetic moments are also given for these baryons.
Speaker: Mrs Zalak Shah (Research Scholar)
• 15:38
Prediction on the discovery channel of doubly charmed baryon 17m
We systematically investigate the weak decays of the doubly charmed baryons, which are helpful for experimental searches for these particles. The branching fractions are studied under the factorization hypothesis for the short-distance contributions and considering the rescattering effect for the long-distance contributions which are significantly enhanced. Comparing all the decay modes, we recommend the processes of $\Xi_{cc}^{++}\to\Lambda_c^+ K^- \pi^+ \pi^+$ and $\Xi_c^+ \pi^+$ as the first priority for experiments to search for the doubly heavy baryons. The LHCb collaboration successfully observed the first double-charm baryon via the decay mode $\Xi_{cc}^{++}\to\Lambda_c^+ K^- \pi^+ \pi^+$ under our suggestion.
Speaker: Dr Fu-Sheng Yu (Lanzhou University)
• 15:55
Implication of chiral symmetry on the heavy-light spectroscopy 17m
Understanding the hadron spectrum is one of the premier challenges in particle physics. For a long time, the quark model has served as an ordering scheme and brought systematics into the hadron zoo. However, many new hadrons that were observed since 2003, including the lowest-lying positive-parity charm-strange mesons $D_{s0}^*(2317)$ and $D_{s1}(2460)$, do not conform with quark model expectations. Various modifications to the quark model and alternative approaches have been proposed ever since to explain their low masses and decay properties. We demonstrate that if the lightest scalar (axial vector) states are assumed to owe their existence to non-perturbative $\pi / \eta/K$-$D^{(*)}/D_s^{(*)}$ scattering, various puzzles in the $D$-meson spectrum get resolved. Most importantly the ordering of the lightest strange and non-strange scalars becomes natural. We show the well constrained amplitudes for Goldstone-Boson-$D/D^*$ scattering are fully consistent with recent high quality data on $B^-\to \pi^-\pi^- D^+$ final states. This implies that the lowest quark-model positive-parity charm mesons, together with their bottom cousins, if realized in nature, do not form the ground-state multiplet. This is similar to the pattern that has been established for the scalar mesons made from light up, down and strange quarks, where the lowest multiplet is considered to be made of states not described by the quark model. In a broader view, the hadron spectrum must be viewed as more than a collection of quark model states.
Speaker: Dr Meng-Lin Du (Helmholtz-Institut f\"ur Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Universit\"at Bonn)
• 16:12
On chiral extrapolations of charmed meson masses and coupled-channel reaction dynamics 17m
We perform an analysis of QCD lattice data on charmed meson masses. The quark-mass dependence of the data set is used to gain information on the size of counter terms of the chiral Lagrangian formulated with open-charm states with $J^P = 0^-$ and $J^P = 1^-$ quantum numbers. Of particular interest are those counter terms that are active in the exotic flavour sextet channel. A chiral expansion scheme where physical masses enter the extrapolation formulae is developed and applied to the lattice data set. Good convergence properties are demonstrated and an accurate reproduction of the lattice data based on ensembles of PACS-CS, MILC, HPQCD, ETMC and HSC with pion and kaon masses smaller than 600 MeV is achieved. It is argued that a unique set of low-energy parameters is obtainable only if additional information from HSC on some scattering observables is included in our global fits. The elastic and inelastic s-wave $\pi D$ and $\eta D$ scattering as considered by HSC is reproduced faithfully. Based on such low-energy parameters we predict 15 phase shifts and in-elasticities at physical quark masses but also for an additional HSC ensemble at smaller pion mass. In addition we find a clear signal for a member of the exotic flavour sextet states in the $\eta D$ channel, below the $\bar K D_s$ threshold. For the isospin violating strong decay width of the $D_{s0}(2317)$ we obtain the range (45 − 49) keV.
Speaker: Dr Xiao-Yu Guo (GSI Helmholzzentrum)
• 16:30 16:50
Coffee Break 20m
• 16:50 21:30
Trip to Novosibirsk (Novosibirsk Opera and Ballet Theatre) 4h 40m
• Thursday, 24 May
• 08:30 10:30
Hidden and Open Charm in Media
Convener: Dr Miguel Ángel Escobedo Espinosa (University of Jyväskylä)
• 08:30
Experimental review of Open Charm in AA collisions 30m
Speaker: Dr XIAOMING ZHANG (Institue of Particle Physics, Central China Normal University)
• 09:00
Experimental review of Quarkonium Production in pA collisions 30m
Speaker: Dr Patrick Robbe (LAL)
• 09:30
Experimental review of Quarkonium Production in AA collisions 30m
One of the major goals of heavy-ion collisions is to search for quark-gluon plasma (QGP) and study its properties. Quarkonium, the bound state of heavy quarks, provides a sensitive probe of QGP because its production yield in QGP is modified by the color-screening effect, heavy quark (re)combination effect etc. In this talk, I will overview the quarkonium results in heavy-ion collisions from the ongoing experimental efforts at RHIC and LHC. The physics implications will also be discussed.
Speaker: Prof. Zebo Tang (University of Science and Technology of China)
• 10:00
Theoretical overview of charmonium evolutions in the hot medium 30m
I will discuss about both $J/\psi$ and $\psi(2S)$ evolutions in different systems (p-Pb, Pb-Pb), focusing on the aspects of (1) $J/\psi$ regeneration connected with charm diffusion and thermalization in the expanding QGP, (2) double ratio $R_{AA}^{\psi(2S)}/R_{AA}^{J/\psi}$ and transitions between $J/\psi$ and $\psi(2S)$ induced by color screening effect on heavy quark potential, (3) charmonium photoproduction from initial electromagnetic fields even in semi-central collisions $b\sim R_A$ (with the existence of QGP), (4) and different final state interactions for $J/\psi$ and $\psi(2S)$ in small system p-Pb as a function of rapidity and $p_T$. Different theoretical models involving above topics will also be briefly introduced and compared.
Speaker: Dr BAOYI Chen (Tianjin University)
• 10:30 11:00
Coffee Break 30m
• 11:00 12:10
Hidden and Open Charm in Media
Convener: Dr Patrick Robbe (LAL)
• 11:00
Open charm in heavy-ion collisions 30m
Speaker: Dr Magdalena Djordjevic (Institute of Physics)
• 11:30
Effective field theory calculations in open charm and charmonium production in media 20m
Heavy quarkonium related observables are very useful to obtain information about the medium created in relativistic heavy ion collisions. The interaction of charmonium or bottomonium with the hot QCD medium created in these collisions can be efficiently described with the use of non-relativistic Effective Field Theories. In this talk I will review recent progress in understanding quarkonium dynamics in a thermal medium with the use of potential non-relativistic QCD (pNRQCD). First I will discuss the medium modifications of the decay width and the binding energy. Using pNRQCD power counting it is possible to identify in which temperature regimes a potential model can describe these modifications and what is the dominant physical process behind the thermal corrections in each case. After that I will discuss the combination of pNRQCD with open quantum systems techniques. This allows to make predictions about the nuclear modification factor that can be compared with experimental measurements.
Speaker: Dr Miguel Ángel Escobedo Espinosa (University of Jyväskylä)
• 11:50
Charmonia at nonzero temperature from high precision lattice QCD computations 20m
The fate of the charmonia as well as the charm quark diffusion coefficients at nonzero temperature are important to understand the observed nuclear modification factors of charmonia as well as open charm mesons in heavy ion collision experiments. In this talk, we will present our recent results on charmonia spectral functions obtained from quenched lattice QCD simulations at $T\in [0.35,2.25]T_c$. The simulations have been performed on very large and fine lattices where charm quarks can be treated relativistically. We will start by showing the temperature dependence of charmonia correlation functions at several temperatures above and below the deconfinement temperature. We will then discuss the temperature dependences of spectral functions and the resulting charm quark diffusion coefficients obtained from the Maximum Entropy Method. Finally we will present the results on the screening masses of charmonia as well as the dispersion relation at nonzero momenta.
Speaker: Mr Hai-Tao Shu (ccnu)
• 12:10 12:40
D oscillations and CP Violation
Convener: Dr Patrick Robbe (LAL)
• 12:10
Searches for direct CPV in charm at LHCb 30m
Speaker: Mr Maxime Schubiger (EPFL)
• 12:40 14:00
Lunch 1h 20m
• 14:00 15:55
Light Hadronic Spectroscopy from Decays of Charm and Charmonia
Convener: Dr Sergey Barsuk (LAL)
• 14:00
Light hadron spectroscopy at BESIII 30m
The BESIII experiment at the electron-positron collider BEPCII is successfully operating since 2008 and has collected large data samples in the tau-mass region, including the world's largest data samples at the $J/\psi$ and $\psi(2S)$ resonances. In particular, decays of them provide a rich and clean environment to study hadrons consisting out of light quarks and search for exotics. In this presentation recent results of the light hadron physics program will be highlighted.
Speaker: Prof. Shuangshi Fang (Institute of High Energy Physics)
• 14:30
Light hadron spectroscopy at BESIII 30m
The BESIII collaboration has collected unprecedentedly large data sets from $e^+ e^-$ collisions in the C.M.S energy range 2-4.6 GeV. These data, in particular $1.3\times10^9$ $J/\psi$ decays and $0.4\times10^9$ $\psi(3686)$ decays, provide a unique environment to study light hadron spectra and to search for exotic states. The talk will cover recent BESIII results including investigation of $X(1835)$, search for glueball states in radiative $J/\psi$ decays, observation of $e^+e^- \to \eta Y(2175)$ at center-of-mass energies above 3.7 GeV, observation of $a_0(980)$-$f_0(980)$ mixing.
Speaker: Dr Igor Denisenko (JINR)
• 15:00
Review of recent results on amplitude analyses 30m
Speaker: Dr Tim Evans (University of Cincinnati)
• 15:30
Form factors of baryons and light hadrons at Belle (cancelled) 25m
Speaker: Prof. Masayuki Niiyama (Kyoto Sangyo Univ.)
• 15:55 16:25
Coffee Break 30m
• 16:25 18:25
Leptonic, Semileptonic, Radiative and Rare Charm Decays
Convener: Dr Andrea Contu (INFN)
• 16:25
D leptonic, semileptonic and rare decays at BESIII 30m
Speaker: Mr Yu Zhang (University of Chinese Academy of Sciences)
• 16:55
Study of $D_s$ decays at BESIII 30m
BESIII has now collected the world's largest $e^+e^-$ annihilation samples taken at $E_{cm} = 4.009$ and $4.178$ GeV, which contain copious charmed-strange mesons. In this talk, I report our recent studies on leptonic and semileptonic decays of the $D_s$ meson, which allow us to extract the CKM matrix elements $|V_{cs(d)}|$ and the decay constants $f_{D_s^+}$ or semileptonic form factors. Our recent preliminary results on $D_s$ hadronic decays are also presented, including $D_s^+ \to p \bar{n}$.
Speaker: Dr Hajime Muramatsu (University of Minnesota)
• 17:25
Mixing and indirect CPV charm measurements at LHCb 30m
Mixing and CP violation in charm LHCb has collected the world's largest sample of charmed hadrons. World's most precise measurements of neutral D-meson mixing parameters and searches for indirect CP violation in charm interactions are presented.
Speaker: Prof. Angelo Carbone (University and INFN Bologna)
• 17:55
Charm semileptonic decays at LHCb 30m
Speaker: Prof. Alberto Lusiani (Scuola Normale Superiore)
• 19:30 22:30
Conference Dinner (The restaurant "Pechki-Lavochki") 3h
• Friday, 25 May
• 09:00 10:50
Leptonic, Semileptonic, Radiative and Rare Charm Decays
Convener: Prof. Angelo Carbone (University and INFN Bologna)
• 09:00
Rare charm decays 25m
Speaker: Prof. Alexey Petrov (Wayne Univ.)
• 09:25
HFLAV: results on charm mixing and CPV 30m
Speaker: Prof. Alan Schwartz (Univ. of Cincinnati)
• 09:55
Short-distance matrix elements for $D^0$-meson mixing from $N_f = 2 + 1$ lattice QCD 25m
We calculate in three-flavor lattice QCD the short-distance hadronic matrix elements of all five $\Delta C=2$ four-fermion operators that contribute to neutral $D$-meson mixing both in and beyond the Standard Model. We use the MILC Collaboration's $N_f = 2+1$ lattice gauge-field configurations generated with asqtad-improved staggered sea quarks. We also employ the asqtad action for the valence light quarks and use the clover action with the Fermilab interpretation for the charm quark. We analyze a large set of ensembles with pions as light as $M_\pi \approx 180$ MeV and lattice spacings as fine as $a\approx0.045$ fm, thereby enabling good control over the extrapolation to the physical pion mass and continuum limit. We obtain for the matrix elements in the $\overline{\mathrm{MS}}-\mathrm{NDR}$ scheme using the choice of evanescent operators proposed by Beneke \emph{et al.}, evaluated at 3 GeV, $\langle D^0|\mathcal{O}_i|\bar{D}^0\rangle = \{0.0805(55)(16), -0.1561(70)(31), 0.0464(31)(9), 0.2747(129)(55), 0.1035(71)(21)\}~\text{GeV}^4$ ($i=1$ - 5). The errors shown are from statistics and lattice systematics, and the omission of charmed sea quarks, respectively. To illustrate the utility of our matrix-element results, we place bounds on the scale of CP-violating new physics in $D^0$ mixing, finding lower limits of about 10 - 50$\times 10^3$ TeV for couplings of $\mathrm{O}(1)$. To enable our results to be employed in more sophisticated or model-specific phenomenological studies, we provide the correlations among our matrix-element results. For convenience, we also present numerical results in the other commonly-used scheme of Buras, Misiak, and Urban.
Speaker: Dr Chia Cheng Chang (Lawrence Berkeley National Laboratory)
• 10:20
Leptonic, semi-leptonic, and rare charm decays at the B-factories 30m
The B factories, Belle and BaBar, were successful in measuring the properties of the B mesons. But the B factories also produce a similar number of D mesons in the electron-positron collisions. The data sets recorded at the B factories allow us to study leptonic, semi-leptonic, and rare D decays. These decays are suppressed in the Standard Model. Therefore, the comparison of the observables extracted from these decays to the Standard Model predictions makes them a useful instrument in the search for new physics. In this contribution I will present an overview of the measurements performed at the B factories.
Speaker: Mr Dmytro Levit (Technical University of Munich)
• 10:50 11:20
Coffee Break 30m
• 11:20 13:05
D oscillations and CP Violation
Convener: Prof. Michael Sokoloff (University of Cincinnati)
• 11:20
Rare charm decays at LHCb 30m
Speaker: Mr Dominik Stefan Mitzel (Physikalisches Institut)
• 11:50
Review of recent developments on leptonic and semileptonic charm decays from lattice QCD 25m
Leptonic and semileptonic decays of charmed mesons are excellent places for the extraction of the CKM matrix elements $|V_{cd}|$ and $|V_{cs}|$ and to provide stringent constraints on possible New Physics scenarios. Lattice QCD provides a non-perturbative method to calculate the hadronic contributions involved in these processes. In this talk, I will review recent progress in the study of D-meson decay constants and semileptonic form factors. In addition, I will present the impact of the latest lattice-QCD results on phenomenology and compare the predictions with the experimental results.
Speaker: Dr Giorgio Salerno (University of Roma Tre & LPT Orsay)
• 12:15
Mixing and CPV measurements at the B-factories 30m
Speaker: Ms Yeqi Chen (University of Science and Technology of China)
• 12:45
D mixing parameter y in the factorization-assisted topological-amplitude approach 20m
We calculate the $D^0-\overline{D}^0$ mixing parameter $y$ in the factorization-assisted topological-amplitude (FAT) approach, considering contributions from $D^{0}\to PP$, $PV$, and $VV$ modes, where $P$ ($V$) stands for a pseudoscalar (vector) meson. The $D^{0}\to PP$ and $PV$ decay amplitudes are extracted in the FAT approach, and the $D^{0}\to VV$ ones with final states in the longitudinal polarization are estimated via the parameter set for $D^{0}\to PV$. It is found that the $VV$ contribution to $y$, being of order of $10^{-4}$, is negligible, and that the $PP$ and $PV$ contributions amount only up to $y_{PP+PV}=(0.21\pm0.07)\%$, a prediction more precise than those obtained in the literature, and much lower than the experimental data $y_{\rm exp}=(0.61\pm0.08)\%$. We conclude that $D^{0}$ meson decays into other two-body and multi-particle final states are relevant to the evaluation of $y$, so it is difficult to have its full understanding in an exclusive approach.
Speaker: Dr Qin Qin (University of Siegen)
• 13:05 14:30
Lunch 1h 25m
• 14:30 16:30
Parallel Session III
Convener: Dr Ivan Logashenko (BINP)
• 14:30
Status of radiative and rare leptonic tau decays at NLO 17m
This talk will be a review of recent developments in the evaluation of NLO QED predictions for the radiative ($\tau \rightarrow l \gamma \nu \bar \nu$) and the rare ($\tau \rightarrow l l l \nu \bar \nu$) tau decays, performed independently by two groups: Fael, Greub, Passera and Pruna, Signer, Ulrich. Fully differential NLO corrections are very important for the analysis of tau measurements aiming at the percent level or better, especially if very stringent phase-space cuts are applied.
Speaker: Dr Matteo Fael (University of Siegen)
• 14:47
Study of radiative decays of the $\Upsilon(1S)$ and of three-body decays of the $J/\psi$ 17m
We report on recent studies of quarkonium decays obtained with the data collected by the BaBar experiment at the PEP-II $e^+e^-$ collider. In particular, we use the entire BaBar dataset to study the reaction $e^+ e^- \to \gamma_{ISR} J/\psi$, with $J/\psi \to \pi^+ \pi^- \pi^0$, $J/\psi \to K^+ K^- \pi^0$, or $J/\psi \to K_S K^\pm \pi^\mp$, and the photon $\gamma_{ISR}$ is produced via Initial-State-Radiation. We measure the relative $J/\psi$ branching fractions and perform a Dalitz plot analysis of each $J/\psi$ decay mode using an isobar model and a Veneziano model. We also present a study of the radiative decays of the $\Upsilon(1S)$ to $\pi^+\pi^-\gamma$ and $K^+K^-\gamma$ final states, performed on the data samples collected at the peak of the $\Upsilon(2S)$ and $\Upsilon(3S)$ resonances. The $\Upsilon(1S)$ is reconstructed from the decay chains $\Upsilon(nS) \to \pi^+\pi^-\Upsilon(1S)$, with $n=2,3$. Branching fractions measurements and spin-parity analyses are reported for the $\Upsilon(1S)$ radiative decays to intermediate resonances observed in the $\pi^+\pi^-$ and $K^+K^-$ mass spectra.
Speaker: Mr Evgeny kozyrev (binp)
• 15:04
Measurements of the branching fractions of the $J/\psi$, $\psi(2S)$ decays to hadrons via ISR at BaBar 17m
There are still less than 50% of the hadronic decays of $J/\psi$ and $\psi(2S)$ known so far. We present an overview of the study of the $J/\psi$ and $\psi(2S)$ production via ISR at BaBar. A few dozens of exclusive final states have been measured, many of them for the first time. Excellent detector performance allows to measure the major decay modes with low systematic errors. We present latest measurements of the $J/\psi$ and $\psi(2S)$ branching fractions to the $\pi \pi \eta$, $K_S K_L \pi^0$, $K_S K_ L \pi^0 \pi^0$, and $K K_S \pi\pi^0$ modes.
Speaker: Prof. Evgeny Solodov (BINP)
• 15:21
The inclusive reconstruction of Charmed mesons on B-factory 17m
We will present inclusive method of the study of double charmed decays with strangeness $B \to \bar{D}^{(*)}D_{s(J)}^{(*)}$. The study based on the missing mass distributions in inclusive transitions $B \to \bar {D}^{(*)} X$, and thus in a way free from the assumptions about resonance decays $D_{s(J)}^{(*)}$. We will also present the perspective of such studies on next generation Belle II experiment.
Speaker: Dr Olga Gzhymkovska (INP PAS)
• 15:38
Measurement of the Decay $\Lambda_c \to \Sigma \pi \pi$ at Belle 17m
Recent model-independent measurements of the absolute branching ratio of the normalization mode $\Lambda_c -> p^+ K^- \pi^+$ by the Belle$^1$ and BES3$^2$ collaborations have significantly increased the precision of previously measured decay channels. BES3 also independently updated the value for the $\Lambda^+_c \to\Sigma^+ \pi^- \pi^+$ mode, however the branching fraction into the $\Lambda^+_c \to\Sigma^0 \pi^0 \pi^+$ decay channel has not been improved upon since the measurement by the CLEO$^3$ collaboration. We report new measurements of the branching fractions of the decays $\Lambda^+_c \to \Sigma^+ \pi^- \pi^+$, $\Sigma^0 \pi^0 \pi^+$ and $\Sigma^+ \pi^0 \pi^0$ based on 711 fb$^{-1}$ of integrated luminosity recorded with the Belle detector at the KEKB asymmetric energy $e^+e^-$ collider near the $\Upsilon(4S)$ resonance (charge conjugated decays are implicitly included). All results are obtained relative to $\Lambda^+_c\to pK^-\pi^+$. This is the first measurement of the $\Lambda^+_c -> \Sigma^+ \pi^0 \pi^0$ channel. The measurements of the other modes are significantly more precise compared to previous analyses and of similar precision to the recent BES3 results. 1 A. Heller et al. (Belle Collaboration) Phys. Rev. D 91, 112009 (2014) 2 M. Ablikim et al. (BESIII Collaboration) Phys. Rev. Lett. 116, 052001 (2015) 3 P. Avery et al. (CLEO Collaboration) Physics Letters B, Volume 325, Issue 1 (1994)
Speaker: Mr Manfred Berger (Stefan-Meyer-Institute, Austrian Academy of Sciences)
• 15:55
Measurements of charmed mesons and baryons in pp and p--Pb collisions with ALICE at the LHC 17m
Heavy quarks (charm and beauty) are produced in hard scattering processes at the early stage of the collision. Charmed-hadron production in small systems is important to test perturbative QCD calculations, to understand cold nuclear matter effects and to test possible collective effects. In addition their abundance is preserved during the subsequent collision stages making them effective probes for the hot and dense QCD medium (QGP) produced in heavy-ion collisions. The measurement of charmed-baryon production, and in particular of the charmed baryon-to-meson ratio ($\Lambda_\mathrm{c}^{+}/\mathrm{D}^{0}$), is sensitive to the charm hadronisation mechanism, which is a non-perturbative process. Moreover the measurements of heavier charmed baryons, for example $\mathrm{\Xi_c^0}$, can be used to quantify the hadronisation of charm quarks into different hadron species. Furthermore, the measurements of charm hadrons in pp and p--Pb collisions constitute the necessary reference for measurements in Pb--Pb collisions. In this talk, the recent measurements of open heavy flavours in pp and p--Pb collisions performed with the ALICE detector will be presented. These results include the $p_\mathrm{T}$-differential production cross-section of non-strange D mesons ($\mathrm D^{0}$, $\mathrm D^{*+}$ and $\mathrm D^{+}$) and of the $\mathrm D_{\mathrm s}^{+}$ meson, and their nuclear modification factor in p--Pb collisions. We also present the recent measurements of the $p_\mathrm{T}$-differential cross section of the $\Lambda_{c}^+$ baryon at mid-rapidity in pp collisions at $\sqrt{s} = 7$ TeV and in p--Pb collisions at $\sqrt{s_{\mathrm{NN}}} = 5.02$ TeV. In addition, the first measurement of $\mathrm{\Xi_c^0}$--baryon production in the decay channel $\mathrm{\Xi_c^0 \to e^{+} \Xi^- \nu_e}$ in pp collisions at $\sqrt{s} = 7$ TeV at the LHC will be presented.
Speaker: Mr Syaefudin Jaelani (Utrecht University)
• 16:12
Charm jet production and properties in pp, p-Pb, and Pb-Pb collisions measured with ALICE at the LHC 17m
In Pb-Pb collisions at the LHC, a hot and dense medium of deconfined quarks and gluons is formed (Quark-Gluon Plasma, QGP). The QGP is conjectured to be the state of matter of the early Universe up to few microseconds after the Big Bang and may still exist in the core of neutron stars. One of the most striking signatures of the QGP formation in heavy-ion collisions is the suppression of jet production. This phenomenon, called jet quenching, is ascribed to the energy lost by the initial parton while traveling through the QGP medium. Heavy quarks lose energy via subsequent elastic scatterings with the medium constituents, and/or through gluon radiation. Theoretical models predict that energy loss depends on the color charge and mass of the hard-scattered parton traversing the medium. Such mass dependence can be studied by measuring the production of hadrons and jets containing heavy-quarks in pp, p-Pb and Pb-Pb collisions at the LHC. In this contribution we will present the measurements of c-jet production in pp, p-Pb and Pb-Pb collisions performed with the ALICE detector at the LHC. The results obtained with pp and p-Pb data will be compared with predictions from event generators. Charm jets are tagged by requiring the presence of a D meson among its constituents. Thanks to the exclusive reconstruction of D-meson hadronic decay channels, the measurement of the jet-momentum fraction carried by the D meson is possible. This provides useful information to investigate charm fragmentation and production processes. The prospects for measuring b-jet production with ALICE will be also discussed.
Speaker: Mr Hadi Hassan (University Grenoble Alpes / LPSC Grenoble)
• 14:30 16:30
Parallel Session IV
Convener: Dr Alexey Nefediev (Lebedev Physical Institute)
• 14:30
Decay $D_s \to \phi \ell^+\nu_{\ell}$ in covariant quark model 17m
The semileptonic charmed meson decays are the ideal tools to explore the various aspects of heavy quark decays. We study the leptonic and semileptonic $D_s$ meson decays ($D_s \to \ell^+ \nu_{\ell}$ and $D_s \to \phi \ell^+ \nu_{\ell}$) in the framework of covariant quark model (CQM) with built-in infrared confinement. The CQM is an effective quantum field approach for the hadronic interaction based on effective Lagrangian of hadrons interacting with the constituent quarks. The required form factors are computed in the entire range of momentum transfer and used to determine semileptonic branching fractions. The computed branching fractions are in close resemblance with the recent BESIII data [arXiv:1709.03680] and other experimental results.
Speaker: Mr Nakul Soni (Applied Physics Department, The Maharaja Sayajirao University of Baroda, Vadodara)
• 14:47
CP violation in charm decays into neutral kaons 17m
We find a new $CP$-violation effect in charm decays into neutral kaons, which results from the interference between two tree (Cabibbo-favored and doubly Cabibbo-suppressed) amplitudes with the mixing of final-state mesons. This effect, estimated to be of order of $10^{-3}$, is much larger than the direct $CP$ asymmetries in these decays, but missed in the literature. It can be revealed by measuring the difference of the time-dependent $CP$ asymmetries in the $D^{+}\to \pi^{+}K_S^0$ and $D_{s}^{+}\to K^{+} K_S^0$ modes, which are accessible at the LHCb and Belle II. If confirmed, the new effect has to be taken into account, as the above direct $CP$ asymmetries are used to search for new physics.
Speaker: Dr Fu-Sheng Yu (Lanzhou University)
• 15:04
A new parametrization for the scalar isoscalar pion form factor 17m
Dispersion theory is a powerful tool for partial wave analyses of decay and scattering processes involving light mesons. However, as a result of the onset of various inelastic channels, its simple single- or two-channel implementations can in practice be applied only up to energies of about $1.1$ GeV. In this talk we introduce an effective parametrization for the isoscalar, scalar pion form factor which preserves the principles of analyticity and unitarity. Furthermore it allows us to introduce higher resonances and inelastic channels and at the same time matches smoothly on the dispersive representation at low energies. We show how it can be applied to decays $\bar{B}_s^0 \rightarrow J/\psi\,\pi^+\pi^-(K^+K^-)$ measured by LHCb. Since the parametrization is analytic it allows us to explore the structure of the form factor in the complex plane giving rise to resonance poles. In order to extract those we use the model-independent and easily applicable approach of Pad\'e approximants.
Speaker: Mr Stefan Ropertz (University of Bonn)
• 15:21
Parametrizations of three-body hadronic B- and D-decay amplitudes 17m
On behalf of my colleagues, I will present a short review on our recent work [1] on parametrizations of weak $B$ and $D$ decays into final states composed of three light mesons, namely the various charge states $\pi\pi\pi$, $K\pi\pi$ and $KK\bar K$. These parametrizations are derived from previous calculations based on a quasi-two-body factorization approach in which two-body hadronic final state interactions are fully taken into account in terms of unitary $S$- and $P$-wave $\pi\pi$, $\pi K$ and $K \bar K$ form factors. They are an alternative to the isobar-model Dalitz-plot parametrizations and can be useful in the interpretation of CP asymmetries. [1] D. Boito, J.-P. Dedonder, B. El-Bennich, R. Escribano, R. Kaminski, L. Lesniak, and B. Loiseau, Parametrizations of three-body hadronic $B$- and $D$-decay amplitudes in terms of analytic and unitary meson-meson form factors, Phys. Rev. D 96, 113003 (2017).
Speaker: Dr Benoit Loiseau (LPNHE (Paris, FRANCE))
• 15:38
Heavy quark expansion for inclusive charm decays 17m
The heavy mass expansion (HME) has been an indispensable tool for precision calculation in flavor physics, especially for bottom hadrons. However, there have been always doubt if the HME is applicable to charm decays with the same success since both $\alpha_s(m_c)$ and $\Lambda_\mathrm{QCD}/m_c$ are not very small parameters. However one can turn the vice into a virtue. Since $\Lambda_\mathrm{QCD}/m_c$ is not that small, there is a larger sensitivity to higher order terms of the HME in charm decays compared to bottom decays. To this end, inclusive semileptonic charm decays may serve as a tool to study the anatomy of the subleading terms of the HME. In this talk I will report about some recent developments in the evaluation of the $\Lambda_\mathrm{QCD}^3/m_c^3$ and $\Lambda_\mathrm{QCD}^4/m_c^4$ terms for semileptonic charm decays. For the charm, the appropriate expansion is a double seires in powers of $m_s/m_c$ as well as in $\Lambda_\mathrm{QCD}/m_c$. The expansion is not just a trivial tailor series of the results for the $b\to c$ transition but it contains also non analytic terms due to the infrared sensitivity to the strange mass emerging at higher order.
Speaker: Dr Matteo Fael (University of Siegen)
• 15:55
Amplitude analysis of multiparticle decay reactions 17m
The nature of the recently discovered exotic charmonium-like states is still an open question. The distinction between different underlying physical pictures often relies on an analysis of the resonance lineshape. In this context, it becomes crucial to know how exactly the amplitude should incorporate resonances and what uncertainties we expect from the formalism. In the talk, I will discuss the construction of the reaction amplitude for the decay B -> Psi pi K, where the exotic Z(4430) signal was observed. Two commonly-used recipes (the tensor formalism and the helicity formalism) provide frameworks to construct the partial-wave amplitude but do not lead to the same answer. I will demonstrate and clarify the differences between these frameworks as well as their impact on the lineshapes. The approach based on analyticity and crossing symmetry which allows minimizing model dependence will be presented.
Speaker: Dr Mikhail Mikhasenko (HISKP, Universität Bonn)
• 16:12
Sequential Coalescence with Charm Conservation in Heavy Ion Collisions 17m
Heavy quarks are only initially produced in nuclear collisions and the number is conserved during the evolution of the system. We determine the sequence of charmed hadron production by solving a relativistic potential model and hydrodynamic equations. By embedding the charm conservation in a sequential coalescence model, the later produced charmed hadrons are suppressed. Combining together with the strangeness enhancement, the charm conservation eﬀect is signiﬁcantly enlarged in yield ratios involving charm-strange hadrons like Ds/D0 in heavy ion collisions.
Speaker: Mr Jiaxing Zhao (Tsinghua University)
• 16:30 17:00
Coffee Break 30m
• 17:00 18:00
Tau lepton Physics
Convener: Dr Pablo Roig (Cinvestav)
• 17:00
Low-energy tests of QCD with tau decay data 30m
Using the most recent release of the ALEPH τ decay data, we report several relevant tests of perturbative and non-perturbative aspects of QCD. We present the most recent determination of the strong coupling constant, from an exhaustive phenomenological analysis that exploited the sensitivity to the QCD coupling in many different ways. Through the study of the left-right two-point correlation function, several order parameters of the QCD chiral symmetry breaking are determined. Implications for the Standard Model prediction of the kaon direct-CP-violating parameter ε′/ε will also be briefly discussed.
Speaker: Prof. Antonio Pich (IFIC, U. Valencia - CSIC)
• 17:30
Hadronic decays of the tau lepton 30m
We review the status of the experimental measurements of tau decays and the tau structure functions and the status and prospects of their elaborations to extract the strong coupling constant, to compute the hadronic contribution to the muon anomaly and to measure the CKM matrix coefficient $V_{\rm us}$.
Speaker: Prof. Alberto Lusiani (Scuola Normale Superiore)
• 18:00 18:20
Closing 20m