International Workshop on e⁺e⁻ collisions from Phi to Psi 2017

26 Jun 2017, 07:30 → 29 Jun 2017, 20:00 Europe/Berlin

Schloss Waldthausen

Achim Denig (JGU Mainz)

Bild-Urheber: Niels Paul Bethe - MESA Animation; Gestaltung: artefont

The 11th edition of the "International workshop on e+e- collisions from Phi to Psi" (PhiPsi17) is organized by the Institute for Nuclear Physics of the Johannes Gutenberg University of Mainz and will be held at Schloss Waldthausen, an early 20th century mansion located in the forests at the north-western Mainz city limits, on June 26-29, 2017.

PhiPsi17 is the continuation of the biennial workshop series, started in Karlsruhe (1996) and in Novosibirsk (1999). The aim is to bring together experimentalists and theorists to review in detail the status of hadron physics at low energy accelerators, share new developments, and discuss the potential of existing and future facilities.

The proceedings of the PhiPsi17 workshop are published in EPJ Web of Conferences Vol. 218.

The workshop will be followed by the XIXth meeting of the Working Group on Radiative Corrections and Monte Carlo Generators for Low Energies (RadioMonteCarLOW), held on June 30th. The aim of this Working Group is to bring together theorists and experimentalists in order to discuss the current status of radiative corrections and Monte Carlo generators at low energies.

First Circular First Circular for PhiPsi17

Poster Conference Poster

Poster Abstracts Program of the Poster Session

Proceedings Template Template for the proceedings

Second Circular Second Circular for PhiPsi17

Monday, 26 June

1 Welcome

Speaker: JGU President Prof. Krausch

2 (g-2)µ Overview

Speaker: Thomas Teubner

Slides tteubner_phipsi17.pdf

3 (g-2)µ HLBL Overview

Speaker: Andreas Nyffeler (Institute for Nuclear Physics, JGU Mainz)

Slides HLbL_PhiPsi_Nyffeler.pdf

4 FNAL (g-2)µ Experiment

Speaker: B. Lee Roberts

Slides Roberts-g2-PhiPsi2017-final-v2.pptx

5 JPARC (g-2)µ Experiment

Speaker: Tsutomu Mibe

Slides phipsi2017_j-parc_g-2-mibe.pptx

6 CMD-3 Overview

Speaker: Ivan Logashenko

Slides PHIPSI2017_Logashenko.pdf

11:00 Coffee break

7 SND Overview Hadronic Cross Section Measurements

Speaker: Tatyana Dimova (Budker Institute of Nuclear Physics/Novosibirsk State University)

Slides Dimova-SND-v5.pdf

8 BABAR Overview Hadronic Cross Section Measurements

Speaker: Konrad Griessinger (University of Mainz)

Slides Griessinger_PhiPsi17.pdf

9 BESIII ISR Measurements

Speaker: Martin Ripka (JGU KPH)

Slides ISRtalk.pdf

10 Measurement of the running of α_em at KLOE

Speaker: Graziano Venanzoni

Slides gv_PHIPSI17_260617.pdf

13:00 Lunch

11 HVP Determination Orsay group

Speaker: Zhiqing Zhang

Slides Phipsi17_zhang.pdf

12 HVP Determination Jegerlehner group

Speaker: Fred Jegerlehner (Humboldt University Berlin/ DESY Zeuthen)

Slides SMalphaetcMainz17_jegerlehner.pdf

13 4 loop QED Calculation of (g-2)µ

Speaker: Matthias Steinhauser

Slides steinhauser_phipsi17.pdf

14 Spacelike Measurement of HVP contribution to (g-2)µ

Speaker: Luca Trentadue

Slides LTrentadue_talk.pdf

15 The theory of e+e- → non-vector states

Speaker: Johann Kuehn

Slides Vortrag-JK.pdf

16:10 Coffee break

16 CMD-3 measurement of e+e- → π+π-

Speaker: Fedor Ignatov (Budker Institute of Nuclear Physics)

Slides PhiPsi17_2pi.pdf

17 KEDR measurement of R_hadronic

Speaker: Korneliy Todyshev (BINP)

Slides todyshev2017.pdf

18 BESIII measurement of R_hadronic

Speaker: Wenbiao Yan

Slides wenbiao.pdf

19 Perspectives for Hadronic Cross Section Measurements at BELLE-II

Speaker: Boris Shwartz

Slides phipsi17-4_shwartz.pdf

20 SND measurement of e+e- → π0 γ

Speaker: Leonid Kardapoltsev (Novosibirsk State University, Budker Institute of Nuclear Physics)

Slides pi0g_phipsi.pdf

19:00 Reception

Tuesday, 27 June

21 The Phokhara and Ekhara event generators

Speaker: Henryk Czyz (Inst. of Physics, Univ. of Silesia)

Slides czyz_phipsi17.pdf

22 The BABAYAGA event generator

Speaker: Carlo Carloni Calame

Slides carloni.pdf

23 Event generators for Multi Hadronic Production in e+e-

Speaker: Rong-Gang Ping

Slides pingrg.pdf

24 Radiative corrections to elastic electron proton scattering and the uncertainty in the proton charge radius

Speaker: Andrej Arbuzov (Joint Institute for Nuclear Research)

Slides arbuzov_Phi-Psi_2017.pdf

25 ISR measurement of electromagnetic form factors of the proton at low Q²

Speaker: Miha Mihovilovic (JGU Mainz)

Slides MihaTalkPhiPsi2017.pdf

10:25 Coffee break

26 Tau theory overview

Speaker: Emilie Passemar (Indiana University/JLab)

Slides EPassemar_phipsi17.pdf

27 Tau studies - Experimental overview

Speaker: Denis Epifanov

Slides epifanov_phipsi17.pdf

28 Status and progress of the HFLAV-Tau group activities

Speaker: Alberto Lusiani (Scuola Normale Superiore and INFN sezione di Pisa)

Slides lusiani-phipsi17.pdf

29 Review Dark Forces

Speaker: Maxim Pospelov

Slides PhiPsi2017pospelov.pdf

30 Dark Photon studies at BABAR

Speaker: Alessandra Filippi (INFN Torino)

Slides psiphi17_filippi.pdf

12:50 Lunch

31 The Dark Photon studies at BELLE

Speaker: Igal Jaegle

Slides igaljaegle_PsiPhi2017.pdf

32 The BDX experiment

Speaker: Marco Battaglieri

Slides battaglieri.pdf

33 Review lepton flavor violation

Speaker: Andre de Gouvea

Slides PHIPSI_clfv.pdf

34 Precision QED systems

Speaker: Robert Szafron

Slides presentation.pdf

16:30 MAMI Tour

Poster Session

Book of Abstracts PosterSession.pdf

35 A Cylindrical GEM Inner Tracker for the BESIII Experiment at IHEP

The Beijing Electron Spectrometer III (BESIII) is a multi-purpose detector collecting data provided by the collisions in the Beijing Electron Positron Collider II (BEPCII), hosted at the Institute of High Energy Physics of Beijing. BESIII has already collected the world's largest sample of $J/\psi$ and $\psi(2s)$. Due to the unprecedented luminosity of the BEPCII, the most inner part of the Multilayer Drift Chamber (MDC) is showing aging effects. A new Inner Tracker is being built, based on the new technology of Cylindrical Gas Electron Multipliers (CGEM). The CGEM-IT project is deploying several new features and innovations with respect to the other state-of-art GEM detector: the $\mu$-TPC and analog readout, exploiting both time and charge measurements, allow to reach a 130 µm spatial resolution in the 1 Tesla magnetic field of the BESIII experimental scenario; the support of anodes and cathodes is now composed of Rohacell, a PMI foam with a very low impact on material budget; a new “jagged” design of the anode allows for the reduction of the inter-strip capacitance. The poster provides an update on the status of the project, with a particular focus on the experimental data collected by planar and cylindrical prototypes with cosmic rays and test beams data. These results are beyond the state of the art for GEM technology in such an intense magnetic field. The CGEM-IT project has been founded by the European Commission in the action H2020-RISE-MSCA-2014.

Speaker: Marco Maggiora (INFN Torino)

Poster 20170627.Maggiora.BESIII_CGEM-IT.v4.pdf

36 Accessing the real part of the amplitudes of the forward scatterings of J/$\psi$ and $\phi$ mesons on the protons from photoproduction at threshold

We provide an updated analysis of the forward J/$\psi$-p scattering amplitude, relating its imaginary part to $\gamma p \to J/\psi p$ and $\gamma p \to c\bar{c}$ cross sections data, and calculating its real part through a once-subtracted dispersion relation. From a global fit to both differential and total cross section data, we extract a value for the spin-averaged J/$\psi$-p s-wave scattering length $a_{\psi p} = 0.046 \pm 0.005$ fm, which can be translated into a J/$\psi$ binding energy in nuclear matter $B_\psi = 2.7 \pm 0.3$ MeV. We estimate the forward-backward asymmetry to the $\gamma p \to e^- e^+$ process around the J/$\psi$ resonance, which results from interchanging the leptons in the interference between the J/$\psi$ production and the Bethe-Heitler mechanisms. To a good approximation this asymmetry depends linearly on $a_{\psi p}$, and can reach values around -25 % for forthcoming J/$\psi$ threshold production experiments at JLab. Its measurement can thus provide a very sensitive observable for a refined extraction of $a_{\psi p}$. We also made a preliminary analysis of the case of $\phi$-p forward scattering. A lack of inclusive cross section data, as well as the absence of a consistent dataset for the exclusive total and differential cross section of the $\phi$ photoproduction off the proton, does not allow us to draw precise constraints on the fit parameters at this point. By fixing the value of Regge slope, for both elastic and inelastic total $\phi$-p scattering cross sections, $\alpha_{el} = \alpha_{inel} = 1.092$ taken from fits of total photoproduction off the proton, we estimate the value of the subtraction constant of the forward elastic amplitude $T_{\phi p}(0) \approx 46.3$, which is approximately two times higher than what we obtained for the J/$\psi$ case. The estimated forward-backward asymmetry was shown to reach values of about -20% for the beam energies $E = 2.2, 4.4$ GeV. The suitable kinematics were investigated for the specific setup of HMS and SHMS detectors of Hall C at JLab. Studies for the other JLab experiments (e.g. GlueX, SOLID) are ongoing.

Speaker: Mr Oleksii Gryniuk (JGU Mainz)

Poster poster.pdf

37 An Improved Limit for $\Gamma_{ee}$ of X(3872) and $\Gamma_{ee}$ Measurement of $\psi(3686)$

Using the data sets taken at center-of-mass energies above 4 GeV by the BESIII detector at the BEPCII storage ring, we search for the reaction $e^+e^-\to\gamma_{\mathrm{ISR}} X(3872)\to\gamma_{\mathrm{ISR}}\pi^+\pi^-J/\psi$ via the Initial State Radiation technique. The production of a resonance with quantum numbers $J^{PC}=1^{++}$ such as the $X(3872)$ via single photon $e^+e^-$ annihilation is forbidden, but is allowed by a next-to-leading order box diagram. We do not observe a significant signal of $X(3872)$, and therefore give an upper limit for the electronic width times the branching fraction $\Gamma_{ee}^{X(3872)}\mathcal{B}(X(3872)\to\pi^+\pi^-J/\psi)<0.13$ eV at the 90% confidence level. This measurement improves upon existing limits by a factor of 46. Using the same final state, we also measure the electronic width of the $\psi(3686)$ to be $\Gamma_{ee}^{\psi(3686)}=2213\pm 18_\mathrm{stat}\pm 99_\mathrm{sys}$ eV.

Speaker: Mr Martin Ripka (JGU KPH)

Slides x3872poster.pdf

38 Beam Dump Experiment (BDX) @ MESA

At the Institute for Nuclear Physics in Mainz the new electron accelerator MESA will go into operation within the next years. In the extracted beam operation (155 MeV, 150 uA) the P2 experiment will measure the weak mixing angle in electron-proton scattering with a very high precision. For the desired accuracy 10,000 hours of operation time are needed and therefore the high-power beam dump of this experiment is ideally suited for a parasitic dark sector experiment. This poster outlines the physical motivation for a Beam Dump Experiment @ MESA that can significantly contribute to DM searches. At MESA there will be a limited but dedicated floor space available for the BDX. On this basis, first ideas, calculations and drawings for such an experiment are shown.

Speakers: Mr Mirco Christmann (KPH), Dr Patrick Achenbach (Mainz University)

Poster poster_christmann.pdf

39 Composite Baryogenesis

The composite models, which address the existing problems of the Standard Model, generally include the excited leptons. I introduce new scenarios for possible generation of the baryon asymmetry of the universe using these new particles. The scenarios do not contradict to the small neutrino masses and the proton stability, and can be tested at the LHC.

Speaker: Dr Dmitry Zhuridov (University of Silesia)

Poster zhuridov_06-2017_poster_Mainz.pdf

40 Dark Photon Search at BESIII with ISR Method

Using a data set of 2.93 fb$^{−1}$ taken at a center-of-mass energy of 3.773 GeV with the BESIII detector at the BEPCII collider, a search for an extra U(1) gauge boson, also denoted as a dark photon, has been performed. We examine the initial state radiation reactions $e^{+}e^{-}\to e^{+}e^{−}\gamma_{ISR}$ and $e^{+}e^{-}\to\mu^{+}\mu^{−}\gamma_{ISR}$ for this search, where the dark photon would appear as an enhancement in the invariant mass distribution of the leptonic pairs. We observe no obvious enhancement in the mass range between 1.5 and 3.4 GeV/$c^{2}$ and set a 90% confidence level upper limit on the mixing strength of the dark photon and the Standard Model photon. We obtain a competitive limit in the tested mass range.

Speaker: Dr Yuping Guo (KPH, JGU Mainz)

Slides Poster-DarkPhoton-PhiPsi2017.pdf

41 Decay of eta' into four pions and its impact on the doubly-virtual eta' transition form factor

It has been shown that the decay amplitude $\eta'\rightarrow \pi^+\pi^-\gamma$ has an important impact on the dispersion-theoretical analysis of the singly-virtual $\eta'$ transition form factor [1]. Consequently, we expect that the *doubly*-virtual transition form factor can be understood in more detail, starting from an analysis of the decay $\eta'\rightarrow2(\pi^+\pi^-)$. It was found that the $\eta'$ decay into four charged pions is clearly dominated by $\rho$ resonances [2]. The thus predicted branching ratio has recently been confirmed by a measurement of the BESIII collaboration [3]. The $a_2$ tensor meson corrects the amplitude of $ \eta' \rightarrow \pi^+\pi^-\gamma$ noticeably [4] and should therefore also be incorporated into the decay at hand. We use a resonance model to describe the tree-level contribution of the $a_2$ to the decay $ \eta' \rightarrow 2(\pi^+\pi^-)$ and amend the resulting amplitude through a dispersive analysis of the universal $\pi\pi$ final-state interactions. This leads to non-factorizing contributions to the doubly-virtual $\eta'$ transition form factor needed for the light-by-light scattering contribution to the anomalous magnetic moment of the muon and will allow to judge the validity of the factorization ansatz currently used therein. References: - [1] C. Hanhart *et al.* (2013), arXiv:1307.5654 [hep-ph] - [2] F. K. Guo, B. Kubis and A. Wirzba (2011), arXiv:1111.5949 [hep-ph] - [3] M. Ablikim *et al.* [BESIII Collaboration] (2014), arXiv:1404.0096 [hep-ex] - [4] B. Kubis and J. Plenter (2015), arXiv:1504.02588 [hep-ph]

Speaker: Ms Judith Plenter (Helmholtz-Institut für Strahlen- und Kernphysik, Bonn-Cologne Graduate School of Physics and Astronomy)

Poster PhiPsi17_JudithPlenter.pdf

42 Description of tensor meson transition form factors at large $Q^2$ within QCD factorization approach

Due to multiple possible polarizations hard exclusive production of tensor mesons by virtual photons or in heavy meson decays offers interesting possibilities to study the helicity structure of the underlying short-distance process. Motivated by the first measurement of the transition form factor $\gamma^*\gamma \to f_2(1270)$ at large momentum transfers by the BELLE collaboration we present an improved QCD analysis of this reaction in the framework of collinear factorization including contributions of twist-three quark-antiquark-gluon operators and an estimate of soft end-point corrections using light-cone sum rules. The results appear to be in a reasonable agreement with the data, in particular the predicted scaling behavior is reproduced in all cases.

Speaker: Nikoilay Kivel (HIM)

43 Development of large scale focal plane detectors for MAGIX

**MAGIX** is a planned experiment that will be implemented at the upcoming accelerator MESA in Mainz. Due to its location in the energy-recovering lane of the accelerator beam-currents up to **1 mA** with a maximum energy of **105 MeV** will be provided for precision experiments. MAGIX itself consists of a jet-target and two magnet-spectrometers. Inside the spectrometers **GEM**-based detectors will be used in the focal plane. The design goals for the detector modules are a spatial resolution of **50 μm**, a size of **1,20 x 0,30 m²** and a minimal material budget. To accomplish these goals we started developing several GEM-prototypes to study different behaviors and techniques for the final detector. The GEMs used are provided by CERN and are trained, stretched and framed in our laboratory. In this contribution the requirements, ongoing development and achieved measurements are presented.

Speaker: Mr Pepe Guelker (KPH - JGU Mainz)

44 Development of the internal Gas-Jet-Target for MAGIX

MAGIX is a planned experiment that will be implemented at the upcoming accelerator MESA in Mainz. Due to its location in the energy-recovering lane of the accelerator beam currents up to 1 mA with a maximum energy of 105 MeV will be provided for precision experiments. MAGIX itself consists of a Jet Target and two magnet-spectrometers. The Jet-Target consists of a Laval-Nozzle and a catcher which is mounted in a high performance pumping system. This contribution is about the hydrodynamics and the technical implementation of the target system.

Speaker: Stephan Marcus Aulenbacher (JGU Mainz)

45 Dispersive reconstruction of the neutral pion transition form factor obeying asymptotic constraints

The neutral pion transition form factor plays prominent roles both in the hadronic light-by-light scattering corrections to the muon anomaly and in the electromagnetic rare decays of the pion. The singly-virtual transition form factor has been investigated in dispersion relations [1], where the form factor in time-like region was predicted based on the $e^+e^-\to 3 \pi$ cross section data and the high-precision space-like form factor was obtained at low energy by analytic continuation. In this work, we generalize the dispersive analysis into the doubly-virtual kinematics, incorporating the celebrated upshots obtained from perturbative quantum chromodynamics [2-6]. The resulting form factor provides a possibility to study the $\pi^0$-pole contribution to the hadronic light-by-light scattering of the muon $g-2$ in a model independent manner with well estimated uncertainty. [1] M. Hoferichter, B. Kubis, S. Leupold, F. Niecknig and S. P. Schneider, *Dispersive analysis of the pion transition form factor*, Eur. Phys. J. C **74** (2014) 3180, [arXiv:1410.4691 [hep-ph]]. [2] G. P. Lepage and S. J. Brodsky, *Exclusive Processes in Quantum Chromodynamics: Evolution Equations for Hadronic Wave Functions and the Form-Factors of Mesons*, Phys. Lett. B **87** (1979) 359. [3] G. P. Lepage and S. J. Brodsky, *Exclusive Processes in Perturbative Quantum Chromodynamics*, Phys. Rev. D **22** (1980) 2157. [4] S. J. Brodsky and G. P. Lepage, *Large Angle Two Photon Exclusive Channels in Quantum Chromodynamics*, Phys. Rev. D **24** (1981) 1808. [5] V. A. Nesterenko and A. V. Radyushkin, *Comparison of the QCD Sum Rule Approach and Perturbative QCD Analysis for $\gamma^\ast \gamma^\ast \to \pi^0$ Process*, Sov. J. Nucl. Phys. **38** (1983) 284. [6] V. A. Novikov, M. A. Shifman, A. I. Vainshtein, M. B. Voloshin and V. I. Zakharov, *Use and Misuse of QCD Sum Rules, Factorization and Related Topics*, Nucl. Phys. B **237** (1984) 525.

Speaker: Long Bai (Bonn University)

46 High-precision measurement of the proton radius with an active hydrogen Time Projection Chamber

One of today’s most pressing question in nuclear physics is the understanding of the so-called "proton radius puzzle". The puzzle originates from a striking discrepancy between the electric charge radius of the proton, extracted from the muonic hydrogen Lamb shift, compared to measurements based on electron-proton scattering experiments and atomic transition measurements in electronic hydrogen. Solving this problem requires experiments approaching the problem in new ways. To address this puzzle, we will perform a high- precision measurement of the differential ep-scattering cross section in the region of low momentum transfer at the Mainz Microtron (MAMI). To perform this experiment, a new-generation detector, consisting of a Hydrogen Time Projection Chamber (TPC) and Forward Tracking System will be constructed, and a new electron beam line at MAMI will be built. The experimental setup will allow us to measure the energy and angle of the recoil proton with unprecedented accuracy as well as the angle of the forward scattered electron. This is a completely new approach compared to other experiments, which mainly focus on the electron angle. A test measurement with a TPC prototype will be conducted at MAMI in August 2017, which will serve as basis for the main experiment.

Speakers: Dr Patrik Adlarson (Johannes Gutenberg Universität-Mainz), Dr Vahe Sokhoyan (Johannes Gutenberg Universität-Mainz)

47 Lattice calculation of the pion transition form factor

We report on the lattice QCD calculation of the π0→γ∗γ∗ form factor with photon virtualities in the range Q2∈[0−1.5]~GeV2. Different lattice spacings and pion masses are used to extrapolate our result to the physical point. First, we check that our results, once extrapolated to the chiral and continuum limit, are compatible with the chiral anomaly. Then, the shape of the form factor is compared to different phenomenological models proposed in the literature and to experimental data in the single-virtual case when one photon is on-shell. From a phenomenological point of view, this form factor determines the π0 pole contribution to hadronic light-by-light (HLbL) scattering in the muon g−2,thought to be dominant.

Speaker: Dr Antoine Gerardin (Institute for Nuclear Physics, University of Mainz)

48 Magix: A versatile experiment for low-energy physics

Running in parallel to the existing MAMI electron accelerator, the new workhorse of the Institute of Nuclear Physics of the University of Mainz is an energy recovering electron recirculator capable of delivering 1 mA polarized currents at 105 MeV to a fix target experiment in its path. The Magix experiment is currently being developed to exploit that power to perform high-precision experiments in that energy range. This poster will present part of the ambitious physics program of that experiment including, among others, the search for new particles like the possible new dark mediators in both the visible and invisible decay channels and the precision spectroscopy below the hadronization threshold to improve the constraints on the electronic radius of the proton and to test the prediction of modern effective field theories.

Speaker: Mr Sabato Stefano Caiazza (KPH Institut, JGU Universitaet Mainz)

49 Measurement of $\Gamma_{ee} * B_{hadrons}$ for J/$\psi$ meson with KEDR detector

We report a new precise measurement J/$\psi$ meson leptonic width performed with the KEDR detector at the VEPP-4M $e^+e^-$ collider. Cross sections for the processes $e^+e^-\to hadrons$ and $e^+e^- \to e^+e^-$ were measured at J/$\psi$ resonance energy range and $\Gamma_{ee}*B_{hadrons}$(J/$\psi$) value was obtained with accuracy about 2%. Leptonic and total widths were calculated, using the table values of the leptonic branching ratios.

Speaker: Mrs Tatyana Kharlamova (BINP)

Poster poster1.pdf

50 Measurement of $\Gamma_{ee} \times \mathcal{B}_{\mu\mu }$ for $\psi(2s)$ meson with KEDR detector

Based on the nine data sets taken with the KEDR detector since 2004 in charmonia region, we report $\Gamma_{ee} \times \mathcal{B}_{\mu\mu} = 19.4 \pm 0.3 \pm 0.4$ eV for $\psi(2s)$ meson. The total luminosity accounted for is more than 6.5 pb$^{-1}$, corresponding to about $4 \times 10^6 \psi(2s)$. There were several scans of the resonance allowing us to know the collider energy spread and several runs where the data was taken at the $\psi(2s)$ peak and slightly below it. The Particle Data Group does not mention any direct measurement of this quantity yet. Instead, many $\psi(2s)$ parameters, including partial widths and branching ratios, are obtained using a complicated simultaneous fit of results of various experiments.

Speaker: Mr Andrey Sukharev (BINP)

Poster poster.pdf

51 Measurement of $e^+ e^- \rightarrow K^+ K^-$ cross section at $E_{cm} = 2.0 - 3.08$ GeV

The cross section of the $e^+e^-\to K^+K^-$ process is measured with data samples collected with Beijing Spectrometer (BESIII) at $\sqrt{s} = 2.00 - 3.08$ GeV. The results are consistent with those of BaBar and with better precision. A structure near $2.2$ GeV is observed with mass $2229.8 \pm 5.3_{stat} \pm 17.2_{syst}$ MeV and width $143.7 \pm 12.0_{stat} \pm 7.8_{syst}$ MeV. The kaon form factor is extracted from $\sigma(e^+e^-\to K^+K^-)$ and compared with theoretical prediction.

Speaker: Mr Dong Liu (USTC)

52 Measurement of J/$\psi$ Decay Widths with an Energy Scan Method

We measure the cross sections of $e^+e^- \to e^+e^-$ and $e^+e^- \to \mu^+\mu^-$ processes using the data set collected with the BESIII detector at fifteen energy points around the $J/\psi$ resonance. By fitting the theoretical cross section curves of the two processes as functions of energy to the measured cross section data simultaneously, the combinations of $J/\psi$ decay widths $\Gamma_{ee}\Gamma_{ee}/\Gamma_{\rm tot}$ and $\Gamma_{ee}\Gamma_{\mu\mu}/\Gamma_{\rm tot}$ are extracted to be ($0.348 \pm 0.008$) keV and ($0.339 \pm 0.005$) keV with a covariance $0.000,037$ keV$^2$. With the fitting results, $\Gamma_{ee}/\Gamma_{\mu\mu}$ is evaluated as $1.025 \pm 0.014$, which proves the lepton universality. Assuming the lepton universality and combining the branching ratio of $J/\psi$ leptonic decay measured by BESIII in 2013, the total width $\Gamma_{\rm tot}$ and the leptonic width $\Gamma_{ll}$ are determined to be ($94.3 \pm 1.9$) keV and ($5.64 \pm 0.10$) keV, respectively.

Speaker: Xingyu Zhou (IHEP Beijing)

53 Quark mass dependence in photon pion scattering

Usually the simulation of scattering processes in lattice QCD is carried out at unphysical high values of the quark masses [1]. Hence, a method to extrapolate data obtained in lattice calculations to physical masses is needed to allow for comparison between theory and experiment. To obtain a sound extrapolation, dispersion relations and chiral perturbation theory (ChPT) can be invoked. While a simple combined approach known as the inverse amplitude method (IAM) allows for a successful extrapolation of $\pi\pi\rightarrow\pi\pi$ data [2], a more complicated framework is needed for inelastic processes such as $\gamma\pi\rightarrow\pi\pi$. By extending the dispersive description derived in Ref. [3], the extrapolation can be performed for $\gamma\pi\rightarrow\pi\pi$. This particular process is interesting due to both its contribution to the anomalous magnetic moment of the muon and its connection to the axial anomaly. References: - [1] Briceno et al.: https://arxiv.org/abs/1507.06622 - [2] Bolton, Briceno, Wilson: https://arxiv.org/abs/1507.07928 - [3] Hoferichter, Kubis, Sakkas: https://arxiv.org/abs/1210.6793v2

Speaker: Mr Malwin Niehus (Helmholtz Institut für Strahlen- und Kernphysik, Universität Bonn and Bonn-Cologne Graduate School of Physics and Astronomy)

Poster poster_malwin_niehus.pdf

54 Recent Results of the Hadronic Cross Sections Measurement of the Processes $e^+e^-\to KKn\pi$ with CMD-3 Detector

After the upgrade of the positron injection facility the electron-positron collider VEPP-2000 started to operate at the end of last year and delivers an excellent luminosity, which is higher than the previous in 2-3 times. The detector CMD-3 has gained a new statistic, which corresponds to integrated luminosity of about 30 pb$^{-1}$. Many processes in the energy region from 1 to 2 GeV go through the production of multihadron events with kaons in the final state. The paper presents preliminary results of measurements of the cross sections for some processes.These new results are badly required to improve the unceraincy of calculation of the hadronic contribution to (g-2)/2 of muon particularly in the light of new experiment in FNAL.

Speaker: Prof. Gennady Fedotovich (Budker institute of nuclear physics)

55 Search for the $\chi_{c1}$ charmonium in direct $e^+e^-$ production

With the high luminosity accelerator -- BEPCII and the BESIII detector located in Beijing, China, for the first time, we are able to search for a non-vector charmoinum -- the $\chi_{c1}$ state in $e^+e^-$ direct production. In order to investigate the full interference line shape of $\chi_{c1}$ with continuum background, we propose to take data with $e^+e^-$ central-of-mass energy 2 MeV below, exactly at, and 2 MeV above the $\chi_{c1}$ nominal mass. From 14th May to 1st June, and 11th June to 13th June, the BESIII detector successfully accumulated 175 $pb^{-1}$ data at 3508.66 MeV, 175 $pb^{-1}$ data at 3510.66 MeV and 38 $pb^{-1}$ data at 3514.6 MeV. Detailed data analysis is ongoing, and the final results will be released soon.

Speaker: Dr Zhiqing Liu (postdoc)

56 Study of $\tau\rightarrow 3\pi \nu_\tau$ within extended RChT including tensor and scalar resonances

We analyze the contribution from intermediate spin–0 and spin–2 resonances to the $\tau\rightarrow 3\pi \nu_\tau$ decay by means of a chiral invariant Lagrangian incorporating these mesons. In particular, we study the corresponding axial-vector form-factors. The advantage of this procedure with respect to previous analyses is that it incorporates chiral (and isospin) invariance and, hence, the partial conservation of the axial-vector current. This ensures the recovery of the right low-energy limit, described by chiral perturbation theory, and the transversality of the current in the chiral limit at all energies.

Speaker: Dr Olga Shekhovtsova (Institute of Nuclear Physics)

Poster shekhovt_phipsi2017.pdf

57 Study of the process $e^+e^- \to\pi^+\pi^-\pi^0\eta$ at the SND detector

The reaction $e^+e^- \to \pi^+\pi^-\pi^0\eta$ has been studied in the experiment with the SND detector at the VEPP-2000 $e^+e^-$ collider. The reaction proceeds via the four intermediate states: $\omega\eta$, $\phi\eta$, $a_0\rho$ and structureless $\pi^+\pi^-\pi^0\eta$ state, which may be, for example, $\rho(1450)\pi$ with $\rho(1450) \to \rho(770)\eta$. The total $e^+e^- \to \pi^+\pi^-\pi^0\eta$ cross section and cross section for the four intermediate states have been measured and fitted in the vector meson dominance model.

Speaker: Mr Alexander Botov (Budker Institute of Nuclear Physics)

Poster phipsi17.pdf

58 Testing $\chi_{c}$ properties at BELLE II

The integrated luminosity in the BELLE II experiment (20-50 ab$^{-1}$) will allow to access information never available before. It was found, within the model implemented in the newly updated Monte Carlo generator EKHARA, that at BELLE II it will be possible to study in detail $\chi_{ci} − \gamma^∗ − \gamma$ form factors through measurements of the reaction $e^+e^- \to e^+e^-\chi_{ci} (\to \gamma J/\psi (\to \mu^+ \mu^-))$. The proposed measurements will also serve as tests of the models predicting the $\chi_{c1}$ and $\chi_{c2}$ electronic widths.

Speaker: Patrycja Kisza (University of Silesia)

Poster POSTER.pdf

59 The crystal Zero Degree Detectors at BESIII

The BESIII experiment based at the BEPCII $e^{+}e^{-}$ collider (Beijing, China) is investigating physics in the charm-$\tau$ region. Processes in which the particles emission peaks towards small polar angles, such as Initial State Radiations (ISR) from $e^{+}e^{-}$ annhiliations, are currently detected with limited efficiency. In order to improve their detections, we propose two small taggers placed at the very forward/backward angles. Each detector is composed of two arrays of 4x3 rectangular-shaped scintillating LYSO crystals, separated by a gap. The scintillation light will be collected by silicon photomultipliers (SiPMs) and the signals will be digitized using sampling Analog-to-Digital Converters (sADC). In this contribution, we present the results from the tests of a single LYSO crystal and the read-out electronics using radioactive sources. Studies of the final setup, using Geant4 based simulation of BESIII and the cZDDs, are also shown. This work is supported by the DFG under contract No. CRC 1044.

Speaker: Dr Brice Garillon (JGU Mainz)

Poster PosterPhiPsi2017_Garillon.pdf

60 The Design and Performance of the Münster Gas-Jet Target for MAGIX at MESA

The experiments at the future electron accelerator MESA (Mainz Energy-recovering Superconducting Accelerator) at the University of Mainz focus on the validity of the Standard Model of particle physics. Thereby, the main interest is the search for dark photons as candidates for dark matter, and precision measurements of fundamental constants, such as the proton radius or the electroweak mixing angle. The MAGIX experiment (MESA Gas Internal target eXperiment) will be located in the energy-recovering sector of this future electron accelerator with energies up to 105 MeV, a beam current of 1 mA, and a high luminosity of $10^{35} \frac{1}{\mathrm{cm}^2 \mathrm{s}} $. MAGIX will consist of a multi-purpose spectrometer and a gas-jet target which was designed, built up, and set into operation at the University of Münster. The gas-jet beam is produced by the expansion of gas within Laval nozzles and provides constant thickness in time and space (e.g. $10^{19} \frac{\mathrm{atoms}}{\mathrm{cm}^2} $ directly behind the nozzle). By cooling and changing the pressure of the gas at the nozzle, the gas-jet target can also be operated in a cluster-jet mode. This offers the possibility to achieve a directed, less divergent beam even at large distances from the nozzle. Thereby, the highest thicknesses with a lower gas flow to improve the vacuum conditions can be achieved. Currently, measurements to characterize the target beam depending on different properties, e.g. different nozzle designs, different stagnation conditions of the gas in front of the nozzle, are performed. For this purpose, a Mach-Zehnder interferometer is used to determine the thickness distribution and the shape of the gas-jet. The design of the Münster gas-jet target and the beam properties will be presented and discussed.

Speaker: Mrs Silke Grieser (WWU Münster)

Poster Grieser_2017.pdf

61 The MUon Scattering Experiment (MUSE) at PSI

The proton is not an elementary particle but has a substructure governed by the interaction of quarks and gluons. The size of the proton is manifest in the spatial distributions of the electric charge and magnetization, which determine the response to electromagnetic interaction. Recently, contradictory measurements of the proton charge radius between muonic hydrogen and electronic probes have constituted the proton radius puzzle, which has been challenging our basic understanding of the proton. The MUon Scattering Experiment (MUSE) in preparation at the Paul-Scherrer Institute (PSI) has the potential to resolve the puzzle by measuring the proton charge radius with electron and muon scattering simultaneously and with high precision, including any possible difference between the two, and with both beam charges. The status of the MUSE experiment will be reported. This work has been supported by the U.S. National Science Foundation and Department of Energy.

Speaker: Prof. Michael Kohl (Hampton University)

62 The OLYMPUS Experiment at DESY

Hard two-photon exchange has been favored theoretically to explain the previously observed discrepancy in measurements of the elastic proton electric-to-magnetic form factor ratio with polarized and unpolarized methods. Several experiments have been carried out to investigate the effects of two-photon exchange. The OLYMPUS experiment at DESY has been one of three dedicated experiments to use comparisons of positron-proton and electron-proton scattering to unequivocally determine the effects of two-photon exchange. Results from the OLYMPUS experiment will be presented. This work has been supported by the U.S. National Science Foundation and Department of Energy.

Speaker: Prof. Michael Kohl (Hampton University)

63 Theoretical Description of the Invariant Mass Distribution of the decay $Y(4260) \to J/ \psi \; \pi^{+} \pi^{-}$

In this work, we aim to provide a physical description of the recent BESIII data on the exotic meson decay, $ Y(4260) \to J/ \psi \; \pi^{+} \pi^{-}$. In the $\psi \pi$ invariant mass distribution, one can observe two peaks, which correspond to the exotic meson $Z_c(3900)$ and its kinematic reflection. Its shape can be parameterized as a S-wave Breit-Wigner and a background, which comes from the final state interactions of two pions. The latter we implement using unitarity and analyticity constraints. In result, a simultaneous description of $\psi \pi$ and $\pi \pi$ invariant mass distributions is achieved.

Speaker: Mr Daniel Molnar (JGU Mainz)

64 Two-photon form factors of the pseudoscalar mesons in Phokhara and Ekhara Monte Carlo generators

Phenomenological model, which describe very well the coupling of the $\pi^0, \eta, \eta^{'}$ mesons to two photons is presented. The model of the form factors is consistent with the data in the space-like region, as well with the data in the time-like region with exception of the $\pi^0$ BaBar data and $\eta$ CMD2 data. The obtained form factors are implemented in Monte Carlo event generator Phokhara and Ekhara and investigation of the impact of radiative corrections for a cross section of $e^+ e^- \to \gamma \pi^0, (\eta, \eta^{'} )$ is studied.

Speaker: Szymon Tracz (University of Silesia)

Wednesday, 28 June

65 Review of XYZ theory

Speaker: Luciano Maiani

Slides Maiani_Mainz_2017.pdf

66 Recent results on XYZ physics from BELLE

Speaker: Roman Mizuk

Slides mizuk_phipsi2017.pdf

67 Recent results on XYZ physics from BESIII

Speaker: Zhentian Sun

Slides PhiPsi2017-Sunzt.pdf

68 Recent results on hadron spectroscopy at LHC

Speaker: Matthew Needham

Slides phitopsi.pdf phitopsi.pptx

10:25 Coffee break

69 Theory of hadronic molecules applied to the XYZ states

Speaker: Christoph Hanhart

Slides hanhart_Mainz_2017_b.pdf

70 Recent issues in heavy quark spectroscopy

Speaker: Marek Karliner

Slides PHI2PSI_Mainz.pdf

71 Meson spectroscopy from lattice calculations

Speaker: Christopher Thomas (University of Cambridge)

Slides CThomas_PsiPhi_June17.pdf

72 Compass Light Quark Spectroscopy

Speaker: Stephan Paul

Slides Paul_Mainz_Juni2017_cleaned.pdf

73 BESIII Light Quark Spectroscopy

Speaker: Xiaoshen Kang

Slides phipsi_light_hardon_bes.pdf

74 Dalitz plot analysis of three body charmonium decays at Babar

Speaker: Wolfgang Gradl (Universität Mainz)

Slides gradl-PHIPSI2017.pdf

13:00 Lunch

75 Proton Radius Review

Speaker: Carl-Edwin Carlson (College of William and Mary)

Slides CEC_PhiPsi_17.pdf

76 The PSI Crema experiment

Speaker: Randolf Pohl

Slides 20170628_PhiPsi_V3_pohl.pdf

77 BESIII results on timelike baryon form factors

Speaker: Alaa Dbeyssi

Slides AD_BESIII_PhiPsi_2017.pdf

78 Nucleon form factors at threshold

Speaker: Alexandr Milstein (Budker Institute of Nuclear Physics)

Slides phipsi2017.pdf

16:00 Departure Tour

17:00 Tour Gutenberg-Museum

Guided tour in the Gutenberg-Museum

18:00 City Tour

Guided city tour in Mainz

20:00 Conference Dinner

Dinner will take place in Heiliggeist

Thursday, 29 June

79 The Muon (g-2)µ Theory Initiative

Speaker: Aida X. El-Khadra

Slides Elkhadra.pdf

80 Lattice calculations for (g-2)µ Mainz

Speaker: Hartmut Wittig

Slides PhiPsi2017.pdf

81 Lattice calculations for (g-2)µ BNL

Speaker: Christoph Lehner

Slides lehner.pdf

82 Theory γ γ interactions

Speaker: Igor Danilkin (Johannes Gutenberg-Universität Mainz)

Slides Danilkin_PhiPsi.pdf

83 Dispersive analysis of light-meson transition form factors

Speaker: Bastian Kubis (Bonn University)

Slides Kubis_PhiPsi17.pdf

10:30 Coffee break

84 Two-photon physics results from Belle and perspectives for Belle II

Speaker: Hideyuki Nakazawa

Slides 1_Nakazawa.pdf

85 Recent Results on Meson Decays from A2

Speaker: Patrik Adlarson (Johannes Gutenberg Universität-Mainz)

Slides PhiPsi17Adlarson.pdf

86 Transition form factor measurement KLOE

Speaker: Elena Perez del Rio

Slides 3_PerezDelRio.pdf

87 Measurements of meson decays and meson transition form factors at CLAS

Speaker: Susan Schadmand (Forschungszentrum Jülich)

Slides Su20170629_PhiPsi17.pdf

88 Measurement of transition form factors in two-photon collisions at BESIII

Speaker: Christoph Florian Redmer (Institut für Kernphysik, Johannes Gutenberg-Universität Mainz)

Slides CFR170629.pdf

89 KLOE eta/eta' physics

Speaker: Marcin Berlowski

Slides 6_Berlowski.pdf

13:00 Lunch

90 X(3915) as a tensor D*D* molecule

Two-photon decays of a tensor D*D* molecule are studied and the suggested approach is applied to the X(3915) charmoniumlike state under the assumption of the latter being a 2++ molecule - a spin partner of the X(3872). It is argued that the existing experimental data disfavour such an identification of this state. Therefore, it is suggested that either the X(3915) has a different exotic nature or it has to be identified as a scalar.

Speaker: Alexey Nefediev (Moscow Institute of Physics and Technology)

LicenseAgreement Nefediev_PhiPsi17_LicenseAgreement-signed.pdf

Paper Nefediev_PhiPsi17_Contribution.pdf

Slides nefediev-phi-psi-2017.pdf

91 Heavy-quark spin-symmetry partners of Zb(10610) and Zb(10650) molecules

Heavy-quark spin-symmetry (HQSS) partners of the isovector bottomonium-like states $Z_b(10610)$ and $Z_b(10650)$ are predicted within the molecular picture. Treating both $Z_b$ states as shallow bound states, we solve the system of coupled-channel integral equations for the contact plus one-pion exchange (OPE) potentials to predict the location of the partner states with the quantum numbers $J^{++}$ ($J=0,1,2$). In particular, we predict the existence of a narrow tensor $2^{++}$ state residing a few MeV below $B^*\bar B^*$ threshold. It is emphasised that the tensor part of the OPE potential in combination with HQSS breaking due to the nonvanishing B*-B mass splitting has a significant impact on the location of the partner states.

Speaker: Vadim Baru (Institute for Theoretical Physics, Ruhr-University Bochum)

Slides Baru_phi_psi_Mainz_2017.pdf

92 HLBL Dispersive theory Mainz

Speaker: Vladiszlav Pauk

Slides 3_pauk.pdf

93 HLBL Dispersive theory Bern

Speaker: Gilberto Colangelo (University of Bern)

Slides lbl-phipsi2017.pdf

94 Overview of the BINP accelerator complex

Speaker: Dmitry Shwartz

Slides phipsi2017_dshwartz.pptx

95 High Intensity e+e- Accelerator - Super Tau Charm Factory

Speaker: Guangshun Huang (University of Science and Technology of China (USTC))

Slides HIEPA-PhiToPsi.pdf

16:15 Coffee break

96 Overview MAMI and MESA at Mainz

Speaker: Kurt Aulenbacher (Institut für Kernphysik, Universität Mainz)

Slides Aulenbacher_PHIPSI2017_29JUN17.pdf

97 Lab report FAIR

Speaker: Lars Schmitt

Slides FAIR_Status_LSchmitt_PhiPsi2017.pdf

98 Lab report JLAB

Speaker: Eugene Chudakov

Slides Chudakov_talk_Mainz_2017.pdf

99 The BELLE-II experiment

Speaker: Changzheng Yuan

Slides 2017_PhiPsi_BelleII_experiment.pdf