The 35th International Symposium on Lattice Field Theory

18-24 June 2017
Palacio de Congresos
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Place

Location: Palacio de Congresos
Date: from 19 Jun 14:30 to 23 Jun 19:10

Conveners

• 19 Jun 14:30 - 16:10
• Prof. Kuramashi, Yoshinobu (University of Tsukuba/RIKEN AICS)
• 19 Jun 16:40 - 18:00
• Dr. von Hippel, Georg (University of Mainz)
• 20 Jun 15:00 - 16:40
• Prof. Syritsyn, Sergey (Stony Brook University)
• 20 Jun 17:10 - 19:10
• Dr. Green, Jeremy (DESY Zeuthen)
• 21 Jun 09:00 - 11:00
• Izubuchi, Taku (Brookhaven National Laboratory & RIKEN-BNL Research Center)
• 21 Jun 11:30 - 13:30
• Prof. Young, Ross (University of Adelaide)
• 22 Jun 15:00 - 16:40
• Blum, Thomas (University of Connecticut)
• 22 Jun 17:10 - 19:10
• Dr. Van de Water, Ruth (Fermilab)
• 23 Jun 15:00 - 16:40
• Prof. Davies, Christine (University of Glasgow)
• 23 Jun 17:10 - 19:10
• Prof. Wittig, Hartmut (Institute for Nuclear Physics, University of Mainz)

Timetable | Contribution List

Displaying 52 contributions out of 52
We present an update on our lattice QCD calculation of the radiative process $\pi \pi \to \pi \gamma^{*}$, which is enhanced by the presence of the $\rho$ resonance. The calculations were performed with 2+1 clover fermions at $m_\pi \approx 320$ MeV and $L$ approx $3.6$ fm, and we have now analyzed the data from the full set of gauge configurations. Using the results of our recent high-precision c ... More
Presented by Dr. Luka LESKOVEC on 23/6/2017 at 16:30
The results of a calculation of the hadronic vacuum polarization contribution to the muon anomalous magnetic moment are presented. We discuss different methods for controlling the infrared regime of the vacuum polarization function. This includes Padé fits, time moments and the time-momentum representation. We correct our results for finite-volume effects by combining the Gounaris-Sakurai ... More
Presented by Prof. Hartmut WITTIG on 22/6/2017 at 15:00
The auxiliary field approach, where one introduces a field whose propagator is the gauge connection along a chosen path, has been used to study renormalization of extended operators in the continuum. If we restrict the paths to straight lines along the axes, the theory can be discretized with an action similar to lattice heavy-quark effective theory in the static limit. Using this theory, extended ... More
Presented by Dr. Jeremy GREEN on 20/6/2017 at 15:00
Magnetic moments of the octet baryons are computed using lattice QCD in background magnetic fields, including the first treatment of the magnetically coupled $\Sigma^0$-$\Lambda$ system. Although the computations are performed for relatively large values of the up and down quark masses, we gain new insight into the symmetries and relations between magnetic moments by working at a three-flavor mass ... More
Presented by Brian TIBURZI on 21/6/2017 at 10:00
We have developed a new way of computing three-point functions. This is based on a factorization with open spin- (and to some extent flavour-) indices that allows us to generate these simultaneously for many different initial and final states and momenta, with little computational overhead. This factorization as well as its implementation will be explained. A new library has been written to ef ... More
Presented by Mr. Marius LÖFFLER on 21/6/2017 at 12:30
Recently, an interquark potential is derived from Bethe-Salpeter(BS) amplitudes of charmonium ground state by Kawanai and Sasaki. The quark potential models with an energy-independent central potential have been successful for understanding the conventional charmonium states especially below the open charm threshold. As one might consider, however, the interquark potential is in general energy- ... More
Presented by Mr. Kazuki NOCHI on 20/6/2017 at 18:50
I will present higher loop order results on a number of calculations within Chiral perturbation Theory. 1) Preliminary results on a three-loop calculation of the pion mass and decay constant in two-flavour ChPT. For the pion mass all needed auxiliary parameters can probably be determined from lattice calculations of $\pi\pi$-scattering. 2) (The main part) Two-loop results at finite volume f ... More
Presented by Prof. Johan BIJNENS on 22/6/2017 at 16:00
Extending the SU(3) flavour symmetry breaking expansion from up, down and strange sea quark masses to partially quenched valence quark masses allows an extrapolation to the charm quark mass. This approach leads to a determination of charmed quark hadron masses and decay constants. Initial results are encouraging and demonstrate the potential of the procedure.
Presented by Dr. Roger HORSLEY on 21/6/2017 at 10:40
I will discuss briefly recent changes in the methodology of computing the baryon EDM on a lattice. The associated correction substantially reduces presently existing lattice values for the proton and neutron theta-induced EDMs, so that even the most precise previous lattice results become consistent with zero. On one hand, this change removes previous disagreements between these lattice results an ... More
Presented by Prof. Sergey SYRITSYN on 21/6/2017 at 9:00
We present results on the isovector and isoscalar nucleon axial form factors including disconnected contributions. The light disconnected quark loops have been computed using exact deflation, while the strange and the charm quark loops have been evaluated using the truncated solver method. Techniques such as the summation and the two-state fits have been employed to control the excited states cont ... More
Presented by Dr. Kyriakos HADJIYIANNAKOU on 19/6/2017 at 15:30
We present lattice QCD calculations of the hadronic light-by-light (HLbL) contribution to the muon anomalous magnetic moment with physical masses at two different lattice spacings. The calculation includes all connected diagrams and the leading, quark-line-disconnected diagrams. Our first calculation has been performed on the $48^3\times 96$ ensemble generated with physical quark masses, $a^{-1}= ... More Presented by Thomas BLUM on 23/6/2017 at 17:10 Type: Parallel Session: Hadron Structure Track: Hadron Structure In local quantum field theories, conserved current operators are obtained by Neother’s theorem. However, this is not the case with effective theories with non-local interactions which are obtained after some of the degrees of freedom are integrated out. Consider for a instance, a system made of a proton and a neutron interacting through one pion exchange potential. The electromagnetic charge i ... More Presented by Kai WATANABE on 20/6/2017 at 16:30 Type: Parallel Session: Hadron Structure Track: Hadron Structure We utilise a new method to calculate electric dipole moments induced by the strong QCD$\theta$-term and the dimension 6 Weinberg term. The method is based on the gradient flow for gauge fields and is free from renormalisation ambiguities at non-vanishing flow times. The results of the nucleon electric dipole moments are calculated on PACS-CS gauge fields (from japan lattice data grid) using$ ... More
Presented by Dr. Jack DRAGOS on 21/6/2017 at 9:20
We compute the leading $QED$ corrections to the hadronic vacuum polarization (HVP) of the photon, relevant for the determination of leptonic anomalous magnetic moments. We work in the electroquenched approximation and use dynamical $QCD$ configurations generated by the CLS initiative with two degenerate flavors of non-perturbatively O($a$) improved Wilson fermions. We consider $QED_{\rm L}$ and ... More
Presented by Mr. Andrea BUSSONE on 22/6/2017 at 18:10
We present an update on our determination of the electromagnetic form factors and axial charge of the nucleon from the $N_\mathrm{f} = 2 + 1$ CLS ensembles with increased statistics and an additional finer lattice spacing. We also investigate the impact of O($a$)-improvement of the currents.
Presented by Dr. Georg VON HIPPEL on 19/6/2017 at 15:10
We present our preliminary result of the electromagnetic form factor of the pion on the large volume configurations $L = 8.1$ fm with $m_\pi = 0.145$ GeV and $m_K = 0.525$ GeV using the stout-smearing clover quark and Iwasaki gauge action at $a^{-1}=2.333$ GeV. From the results at small momentum transfer we determine the mean square charge radius at the physical $m_\pi$ and $m_K$ using the ne ... More
Presented by Junpei KAKAZU on 23/6/2017 at 13:00
The well-known discrepancy in the muon $g-2$ between experiment and theory demands further theory investigations in view of the upcoming new experiments. One of the leading uncertainties lies in the hadronic light-by-light scattering contribution (hlbl), that we address with our position-space approach. In this talk we will focus on exploratory studies of a fermion loop without gluon ex ... More
Presented by Mr. Nils ASMUSSEN on 23/6/2017 at 17:50
We present the first attempt to apply lattice OPE with a fictitious heavy quark to calculate higher moments of the pion light-cone wavefunction. In this talk, we first discuss briefly the approach which was introduced in hep-lat/0507007. Then we discuss the relevant correlators and strategy to extract the moments. Finally, we present preliminary numerical results.
Presented by Dr. santanu MONDAL on 23/6/2017 at 13:40
We determine the pion distribution amplitude from three-point functions, where two currents are at the same time with a space-like separation. Having control over the discretization effects turned out to be mandatory. This can be achieved by the choice of suitable channels and by taking into account discretization effects to leading order in the strong coupling. Furthermore, it is necessary to hav ... More
Presented by Mr. Philipp WEIN on 20/6/2017 at 16:10
We present a new approach to extracting continuum quasi distributions from lattice QCD. Quasi distributions are defined by matrix elements of a Wilson-line operator extended in a spatial direction, evaluated between nucleon states at finite momentum. We propose smearing this extended operator with the gradient flow to render the corresponding matrix elements finite in the continuum limit. This pro ... More
Presented by Dr. Christopher MONAHAN on 20/6/2017 at 15:20
In our previous work, the connected and leading disconnected hadronic light-by-light contributions to the muon anomalous magnetic moment (g - 2) have been computed using lattice QCD ensembles corresponding to physical pion mass generated by the RBC/UKQCD collaboration. However, the calculation is expected to suffer from a significant finite volume error, which is only power-law suppressed. In this ... More
Presented by Taku IZUBUCHI on 23/6/2017 at 17:30
We present a lattice calculation of the Hadronic Vacuum Polarization (HVP) contribution of the strange and charm quarks to the anomalous magnetic moment of the muon including leading-order electromagnetic corrections. We employ the gauge configurations generated by the European Twisted Mass Collaboration (ETMC) with $N_f = 2+1+1$ dynamical quarks at three values of the lattice spacing ($a \simeq 0 ... More Presented by Dr. Simula SILVANO on 22/6/2017 at 18:30 Type: Parallel Session: Hadron Structure Track: Hadron Structure We present a progress report on the Fermilab Lattice, HPQCD, and MILC Collaborations’ calculation of the hadronic vacuum polarization contribution to the muon anomalous magnetic moment (g-2). This calculation is needed in order to make full use of the upcoming Fermilab and J-PARC experiments to measure the muon g-2 to higher precision and improve the sensitivity to physics beyond the Standard M ... More Presented by Dr. Ruth VAN DE WATER on 22/6/2017 at 15:40 Type: Parallel Session: Hadron Structure Track: Hadron Structure In order to perform high precision calculations in lattice QCD for observables of physical interest, especially for dimensionful quantities, it is important to be able to determine the lattice spacing with high accuracy. One choice for scale setting is the observable$w_0$based on the Wilson flow. It is relatively easy to measure on individual ensembles with high precision. However the value of$ ... More
Presented by Mr. Lukas VARNHORST on 21/6/2017 at 11:50
We present results for the QED and strong isospin breaking corrections to the hadronic vacuum polarization using $N_f=2+1$ Domain Wall fermions. QED is included in an electro-quenched setup using two different methods, a stochastic and a perturbative approach. Results and statistical errors from both methods are directly compared with each other.
Presented by Dr. Vera GUELPERS on 22/6/2017 at 17:30
Modern advances in experimental techniques now make it possible to test the weak interaction in nucleon/nuclear systems. In order to reliably interpret such measurements as tests of the standard model, it is often a necessity to make the assumption of good charge symmetry underlying the hadronic/nuclear interactions. Recent lattice QCD simulations have started to constrain the charge symmetry brea ... More
Presented by Dr. James ZANOTTI on 19/6/2017 at 17:20
We present results for the isovector and isoscalar charges of the nucleon. The 2+1+1-flavor calculations were done using MILC HISQ ensembles with three lattice spacings a=0.12, 0.09, 0.06 fm and three pion masses approximately 310, 220, 130 MeV. The 2+1-flavor clover calculations were done on four ensembles with approximately 300 and 190 MeV pion masses.
Presented by Dr. Rajan GUPTA on 19/6/2017 at 12:30
We present lattice QCD results by the BMW collaboration for the leading-order contribution of the hadron vacuum polarization (LO-HVP) to anomalous magnetic moments of all charged leptons. Calculations are performed with u, d, s and c quarks at their physical masses, in volumes of linear extent larger than 6 fm, and at six values of the lattice spacing, allowing for controlled continuum extrapolati ... More
Presented by Dr. Kohtaroh MIURA on 22/6/2017 at 15:20
We report our study of finite volume effect in the leading hadronic contribution to muon g-2 on gauge ensembles with Nf=2+1 dynamical clover fermions generated by PACS collaboration . We compare connected HVP with different physical volumes, from 5.4 -- 8 fm^4, in a fixed lattice spacing a^-1=2.33 GeV in physical pion, We also estimate an extrapolated value into the infinite volume limit and discu ... More
Presented by Dr. Eigo SHINTANI on 22/6/2017 at 17:10
We present a study of the isospin-breaking corrections to pseudoscalar meson masses using the gauge configurations produced by the ETM Collaboration with $N_f=2+1+1$ dynamical quarks at three lattice spacings varying from 0.089 to 0.062 fm. Our method is based on a combined expansion of the path integral in powers of the small parameters $(m_d - m_u)/\Lambda_{QCD}$ and $\alpha_{em}$, where $m_f$ i ... More
Presented by DAVIDE GIUSTI on 22/6/2017 at 18:50
Measurements and theoretical calculations of meson form factors are essential for our understanding of internal hadron structure and QCD, the dynamics that bind the quarks in hadrons. The pion form factor has been measured at small momentum transfer (Q^2) by scattering from atomic electrons and from scattering of electrons from the pion cloud around a proton. On the other hand, in the limit of ver ... More
Presented by Dr. Jonna KOPONEN on 23/6/2017 at 13:20
We present our preliminary results on the calculation of hadronic light-by-light forward scattering amplitudes using vector four-point correlation functions computed on the lattice. Using a dispersive approach, these forward scattering amplitudes can be described by $\gamma^* \gamma^* \to$ hadrons fusion cross sections and then compared with phenomenology. We show that only a few states are needed ... More
Presented by Dr. Antoine GERARDIN on 23/6/2017 at 18:10
We have calculated the magnetic moments of vector ro and K* mesons in lattice gauge theory for various masses of the light and strange quarks. The dependence of the g-factor on the pion mass was explored. The extrapolation to the phisical pion mass has been carried out.
Presented by Dr. Luschevskaya ELENA on 21/6/2017 at 10:20
We report recent progress in nonperturbative renormalization of the hadron quasi-distributions obtained through large-momentum effective theory (LaMET). We discuss the effects of the renormalization the quasi-distribution; final results converted to $\overline{MS}$ are shown.
Presented by Prof. Huey-Wen LIN on 20/6/2017 at 16:00
We present results for the isovector axial, (induced) pseudoscalar, electric, and magnetic form factors of the nucleon. The calculation was done using MILC 2+1+1-flavor HISQ ensembles with three lattice spacings 0.12, 0.09, 0.06 fm and three pion masses, approximately, 310, 220, 130 MeV. The same calculation is performed with the 2+1-flavor clover ensembles with, approximately, 300 and 190 MeV pio ... More
Presented by Dr. Yong-Chull JANG on 19/6/2017 at 12:50
We report on an analysis of the average quark momentum fraction of the nucleon and related quantities using $N_f=2+1$ Wilson fermions. Computations are performed on four CLS ensembles covering three values of the lattice spacing at pion masses down to $M_\pi \approx 200\,\mathrm{MeV}$. Several source-sink separations ($\sim 1.0\,\mathrm{fm}$ to $\sim 1.4\,\mathrm{fm}$) are used to assess excited-s ... More
Presented by Dr. Konstantin OTTNAD on 21/6/2017 at 12:50
I present continuum-limit results for the scalar quark content of the nucleon computed on BMW 3-HEX ensembles. The contents are determined, from the quark-mass dependence of the nucleon mass, through the Feynman-Hellman theorem. I describe a method that avoids a separate computation of quark-mass renormalization constants. Individual up- and-down quark contents of the proton and neutron are comput ... More
Presented by Dr. Christian HOELBLING on 21/6/2017 at 11:30
The conventional approach for calculating the nucleon radius on a finite-size lattice requires interpolation of form factors in the quantized momentum transfer $Q^2$. This interpolation is model-dependent and is therefore a source of systematic uncertainty. Recently, we have presented a derivative method for computing the isovector Dirac radius and the anomalous magnetic moment of the nucleon dire ... More
Presented by Nesreen HASAN on 19/6/2017 at 17:00
We present an update on our results of nucleon form factors measured on a large-volume lattice $(8.1 \mathrm{fm})^4$ at almost the physical point in 2+1 flavor QCD. The configurations are generated with the stout-smeared $\mathcal{O}(a)$ improved Wilson quark action and Iwasaki gauge action at $\beta=1.82$, which corresponds to the lattice spacing of 0.085 fm. The pion mass at the simulatio ... More
Presented by Mr. Natsuki TSUKAMOTO on 19/6/2017 at 15:50
Current status of nucleon-structure calculations using the RBC and RBC+UKQCD 2+1-flavor domain-wall-fermion (DWF) dynamical lattice-QCD ensembles is reported.
Presented by Dr. Shigemi OHTA on 19/6/2017 at 16:40
It is important to correct for finite-volume (FV) effects in the presence of QED, since these effects are typically large due to the long range of the electromagnetic interaction. We recently made the first lattice calculation of electromagnetic corrections to the hadronic vacuum polarisation (HVP). For the HVP, an analytical derivation of FV corrections involves a two-loop calculation which has n ... More
Presented by Mr. James HARRISON on 22/6/2017 at 17:50
Recently, methods that allow for the computation of parton distribution functions in lattice QCD have been proposed. In particular, it has been argued that time-local, and spatially non-local Euclidean matrix elements can be used as probes of hadronic structure and, in certain limits, light-cone parton distribution functions can be obtained. However, approaching these limits presents both numerica ... More
Presented by Prof. Kostas ORGINOS on 20/6/2017 at 15:40
The partonic and electromagnetic structure of the proton has been studied extensively over the past few decades. There is now extensive knowledge of the longitudinal momentum distributions of quarks and gluons in the proton. Nevertheless, there are gaps in the experimental coverage and it is hence highly desired to have robust results from numerical simulations in lattice QCD — in addition to es ... More
Presented by Prof. Ross YOUNG on 20/6/2017 at 15:50
We present results for the renormalization of gauge invariant  nonlocal fermion operators  which contain a Wilson line, to one loop level in lattice perturbation theory. Our calculations have  been performed for Wilson/clover fermions and a wide class of Symanzik improved gluon actions.   The extended nature of such `long-link' operators results in a nontrivial renormalization,  in ... More
Presented by Prof. Haralambos (Haris) PANAGOPOULOS on 20/6/2017 at 15:10
Matching of the quasi parton distribution functions between continuum and lattice is addressed using lattice perturbation theory. Specifically, we use Wilson-type fermions in the analysis. The matching is done for non-local quark bilinear operators with Wilson line. We also discuss operator mixing in the renormalization for the non-local operators based on a symmetry argument.
Presented by Dr. Tomomi ISHIKAWA on 20/6/2017 at 16:20
One of these systematic errors in the lattice computation of the HVP contribution to muon $g-2$ is that associated with the extrapolation to the physical pion mass. We investigate this extrapolation assuming lattice pion masses in the range of 200 to 400 MeV with the help of two-loop chiral perturbation theory, and find that such an extrapolation is unlikely to lead to control of this systematic ... More
Presented by Prof. Maarten GOLTERMAN on 22/6/2017 at 16:20
We present the current status of extracting parton distribution functions (PDFs) from the quasi-PDF approach by the European Twisted Mass Collaboration. We show our results for two ensembles of gauge field configurations, at a non-physical pion mass of around 370 MeV and preliminary results at the physical pion mass. We also discuss our recent progress in renormalization of the matrix elements for ... More
Presented by Dr. Krzysztof CICHY on 20/6/2017 at 15:30
A method to probe second order electroweak interactions in light nuclei is proposed and explored with a focus on double-β decay. The potential importance of short-distance nuclear effects in double-β decay is assessed using a lattice QCD calculation of the nn→pp transition and effective field theory methods. These effects, encoded in the isotensor axial polarisability, are found at the unphysi ... More
Presented by William DETMOLD on 23/6/2017 at 14:00
This presentation will examine the structure of the ground state nucleon and its finite-volume excitations from three different perspectives. Using new techniques to extract the relativistic components of the nucleon wave function, we'll explore the node structure of both upper and lower components of the nucleon wave function and reveal the manner in which a non trivial role for gluonic compon ... More
Presented by Prof. Derek LEINWEBER on 19/6/2017 at 17:40
We report on progress on computing the quark contributions to the nucleon spin as well as the quark contributions to the nucleon mass, the sigma-terms. The present work is carried out on $N_f=2+1$ CLS ensembles of non-perturbatively improved Wilson fermions, down to a pion mass of about 220 MeV.
It is a common problem in In lattice QCD calculations of hadron masses with annihilation channel that the signal falls off in time separation while the noise remains constant. In addition, the disconnected insertion calculation in the three-point function and the calculation of the neutron electric dipole moment (nEDM) with the $\theta$ terms suffer from a noise due to the $\sqrt{V}$ fluctuation. ... More