Conveners
QCD in searches for physics beyond the Standard Model
- Thomas Blum
QCD in searches for physics beyond the Standard Model
- Maarten Golterman (San Francisco State University)
QCD in searches for physics beyond the Standard Model
- Vera Guelpers (University of Edinburgh)
- Finn Stokes (Forschungszentrum Jรผlich GmbH)
QCD in searches for physics beyond the Standard Model
- Takashi Kaneko (KEK)
- Davide Giusti (University of Regensburg)
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Dr Finn M. Stokes (Forschungszentrum Jรผlich GmbH)26/07/2021, 13:00Particle physics beyond the Standard ModelOral presentation
The leading hadronic vacuum polarisation contribution to $(g-2)_\mu$
was recently determined by the Budapest-Marseille-Wuppertal
collaboration to sub-percent precision, providing for the first
time an ab-initio calculation of this quantity with errors comparable
to phenomenological determinations.To reach this unprecedented level of precision, a number of
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critical issues needed to be... -
Kalman Szabo (Forschungszentrum Julich)26/07/2021, 13:15QCD in searches for physics beyond the Standard ModelOral presentation
In this talk we present in detail the continuum extrapolation procedure of the
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recent determination of the leading order hadronic vacuum polarization contribution to the muon anomalous magnetic moment from the Budapest-Marseille-Wuppertal collaboration (arxiv:2002.12347). -
Shaun Lahert (University of Illinois at Urbana-Champaign)26/07/2021, 13:30QCD in searches for physics beyond the Standard ModelOral presentation
We present an update, from the Fermilab Lattice, HPQCD, and MILC collaborations, of our results for the light-quark, connected contribution to the hadronic vacuum polarization correction to the muonโs anomalous magnetic moment. The calculation is performed on 2+1+1 highly-improved staggered quark (HISQ) ensembles with physical pion mass at four lattice spacings (0.15fm-0.06fm). We also present...
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Prof. Christopher Aubin (Fordham University)26/07/2021, 13:45QCD in searches for physics beyond the Standard ModelOral presentation
We present updated results for the light-quark connected part of the leading hadronic contribution to the muon gโ2 from configurations with 2+1+1 flavors of HISQ quarks using the time-momentum representation of the electromagnetic current correlator. We have added statistics on two ensembles as well as a fourth lattice spacing using configurations that have been generated by the MILC...
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Lukas Varnhorst (Aix-Marseille University)26/07/2021, 14:00QCD in searches for physics beyond the Standard ModelOral presentation
Recently, the hadronic vacuum polarization contribution to the anomalous
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magnetic moment of the muon was determined by the BMW collaboration with
sub-percent precision. Such a precision requires to
control many sources of uncertainty. One of these is the uncertainty
in the determination of the lattice spacing.
In this talk, we present the scale setting entering this computation.... -
Lena Funcke (Perimeter Institute)26/07/2021, 14:15QCD in searches for physics beyond the Standard ModelOral presentation
The infamous strong CP problem in particle physics can in principle be solved by a massless up quark. In particular, it was hypothesized that topological effects could substantially contribute to the observed nonzero up-quark mass without reintroducing CP violation. Alternatively to previous work using fits to chiral perturbation theory, in this talk we present direct lattice QCD computations...
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Sergey Syritsyn (JLab Theory Group)26/07/2021, 14:30QCD in searches for physics beyond the Standard ModelOral presentation
Proton decay is a long-sought manifestation of baryon number violation predicted by Grand Unification and expected due to baryon asymmetry of the Universe. Amplitudes of such decay in various channels depend on proton structure determined by nonperturbative QCD dynamics and have to be determined on a lattice. We report results of a recent calculation of these amplitudes using chirally...
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Andrew Zhen Ning Yong (University of Edinburgh)26/07/2021, 14:45QCD in searches for physics beyond the Standard ModelOral presentation
In recent years, lattice determinations of non-perturbative quantities such as $f_K$ and $f_\pi$, which are relevant for $V_{us}$ and $V_{ud}$, have reached an impressive precision of O(1%) or better. To make further progress, electromagnetic and strong isospin breaking effects must be included in lattice QCD simulations.
We present the status of the RBC&UKQCD lattice calculation of...
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Pengxiang Ma (Peking University)26/07/2021, 21:00QCD in searches for physics beyond the Standard ModelOral presentation
We present a lattice QCD calculation of the axial $\gamma$W-box diagrams relevant for the kaon semilep-leptonic decays. We utilize a recently proposed method, which connects the electroweak radiative corrections in Sirlin's representation to that in chiral perturbation theory. It allows us to use the axial $\gamma$W-box correction in the SU(3) limit to obtain the low energy constants for...
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Takashi Kaneko (KEK)26/07/2021, 21:15QCD in searches for physics beyond the Standard ModelOral presentation
We calculate the $B\to D^{(*)}\ell\nu$ form factors in 2+1 flavor
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relativistic lattice QCD by employing the Moebius domain-wall action
for all quark flavors. Our simulations are carried out at lattice cut-offs
$a^{-1} \sim 2.5$, 3.6 and 4.5 GeV with varying bottom quark masses
up to 0.7 $a^{-1}$ to study heavy quark mass dependence and
discretization effects. We extrapolate the form... -
Takeshi Yamazaki26/07/2021, 21:30QCD in searches for physics beyond the Standard ModelOral presentation
We present preliminary results for the kaon semileptonic form factors
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using one of the PACS10 configuration sets, whose physical volume is
(10.2 fm)$^4$ at the physical point with the lattice spacing of 0.064 fm.
The configuration was generated using the Iwasaki gauge action and $N_f=2+1$
stout-smeared clover quark action. The value of |$V_{us}$| is determined
using the interpolated... -
Christopher Kane (University of Arizona)26/07/2021, 21:45QCD in searches for physics beyond the Standard ModelOral presentation
Two important sources of systematic errors in lattice QCD calculations of radiative leptonic decays are unwanted exponentials in the sum over intermediate states and unwanted excited states created by the meson interpolating field. Performing the calculation using a 3d sequential propagator allows for better control over the systematic uncertainties from intermediate states, while using a 4d...
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Masaaki Tomii26/07/2021, 22:00QCD in searches for physics beyond the Standard ModelOral presentation
We calculate $K \to \pi\pi$ matrix elements using periodic boundary conditions as an independent calculation from our previous calculation with G-parity boundary conditions. We present our preliminary results for physical masses on a $24^3, a^{-1}=1$ GeV, $2+1$-flavor Mobius DWF ensemble generated by the RBC and UKQCD collaborations and discuss the prospect for high-precision computation of...
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Saurabh Kadam (University of Maryland College Park)26/07/2021, 22:15QCD in searches for physics beyond the Standard ModelOral presentation
Observation of neutrinoless double-beta $(0\nu\beta\beta)$ decay, a beyond the standard model process that violates lepton number conservation, would imply that neutrinos are Majorana fermions. In order to draw reliable conclusions from the current experimental limits and potential future discoveries, it is important to reduce the uncertainties in the theoretical predictions of its decay rate....
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Dr Tanmoy Bhattacharya (Los Alamos National Laboratory)26/07/2021, 22:30QCD in searches for physics beyond the Standard ModelOral presentation
We present results for the neutron electric dipole moment due to the to dimension 4 and dimension 6 gluonic CP violation, and the isovector quark chromoelectric dipole moment using clover valence quarks on HISQ dynamical ensembles. For the gluonic operators, we use the gradient flow scheme to obtain divergence-free continuum results. For the chromoelectric dipole moment operator, we use the...
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Michael Abramczyk (University of Connecticut)26/07/2021, 22:45QCD in searches for physics beyond the Standard ModelOral presentation
We will present preliminary findings on improving the lattice calculation of the neutron electric dipole moment from the ฮธ term in QCD. The neutron EDM is highly correlated with the lowest lying modes of the Dirac operator. We take advantage of this with a full volume sampling for the low mode part of the quark propagator in order to increase statistics. This augments the all-mode averaging...
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Hartmut Wittig27/07/2021, 05:00QCD in searches for physics beyond the Standard ModelOral presentation
The Fermilab experiment recently published their new measurement of the anomalous magnetic moment of the muon, confirming the Brookhaven's measurement with a comparable precision. Combining those two results and using the theory estimate published by the "Muon $g-2$ theory initiative", a discrepancy of about 4 sigmas is observed between experiment and the theory prediction based on the...
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Christoph Lehner (University of Regensburg & BNL)27/07/2021, 05:15QCD in searches for physics beyond the Standard ModelOral presentation
The Euclidean time windows defined in RBC/UKQCD 2018 provide a means to test the consistency of different lattice results as well as the consistency with the data-driven R-ratio results on a short timescale. This is of particular urgency due to an apparent emerging tension between data-driven results and some lattice results. I will present an update to the 2018 RBC/UKQCD result for Euclidean...
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Davide Giusti (University of Regensburg)27/07/2021, 05:30QCD in searches for physics beyond the Standard ModelOral presentation
We present a lattice calculation of the Euclidean position-space windows contributing to the leading-order hadronic vacuum polarization term of the muon anomalous magnetic moment $a_\mu$.
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Short-, intermediate- and long-distance windows are considered in order to isolate different scales sensitive to specific integration ranges of experimental time-like data used in the R-ratio.
By adopting... -
Leonardo Giusti (Universita & INFN, Milano-Bicocca (IT))27/07/2021, 05:45QCD in searches for physics beyond the Standard ModelOral presentation
The first results from the Fermilab E989 experiment have confirmed the long-standing tension between the experimental determination of the muon anomalous magnetic moment $a_\mu=(g_\mu-2)/2$ and its SM determination using the dispersive approach. In order to match the expected final precision from E989, the current uncertainty on ab initio determinations using lattice QCD must be decreased by a...
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Andreas Risch (Deutsches Elektronen-Synchrotron DESY)27/07/2021, 06:00QCD in searches for physics beyond the Standard ModelOral presentation
The anomalous magnetic moment of the muon $a_{\mu}$ and the running of the electromagnetic coupling $\alpha$ play a fundamental role in beyond Standard Model (SM) physics searches. Non-perturbative hadronic contributions to both quantities, which are related to the hadronic vacuum polarization (HVP) function consisting of two electromagnetic currents, are a main source of uncertainty in the SM...
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Letizia Parato (Aix Marseille Universitรฉ)27/07/2021, 06:15QCD in searches for physics beyond the Standard ModelOral presentation
Recently, the Budapest-Marseille-Wuppertal collaboration has achieved a sub-percent precision in the evaluation of the HVP contribution to the muon g-2. At this level of precision, pure isospin-symmetric QCD is not sufficient. In the talk we will review how QED and strong isospin breaking effects have been included in our work. Isospin-breaking is implemented by expanding the relevant...
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Willem Verplanke (CPT Marseille)27/07/2021, 06:30QCD in searches for physics beyond the Standard ModelOral presentation
Transition form factors of light pseudoscalar mesons ($\pi^0$, $\eta$ and $\eta^{\prime}$) play a crucial role in computing the hadronic light-by-light contribution to the muon anomalous magnetic moment.
We present first results toward the extraction of these form factors using lattice QCD with staggered fermions on $N_f=2+1+1$ gauge ensembles of the Budapest-Marseille-Wuppertal...
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Sebastian Andreas Burri (Universitรคt Bern)27/07/2021, 06:45QCD in searches for physics beyond the Standard ModelOral presentation
We report on our computation of the pion transition form factor $\mathcal{F}_{\pi \rightarrow \gamma^* \gamma^*}$ from twisted mass lattice QCD, to determine the numerically dominant light pseudoscalar pole contribution for the analysis of hadronic light-by-light scattering in the muon $g-2$. The pion transition form factor is computed directly at the physical point. We present first results...
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En-Hung Chao (Johannes Gutenberg University Mainz)27/07/2021, 07:00QCD in searches for physics beyond the Standard ModelOral presentation
The tension between theory and experiment for the anomalous magnetic moment of the muon ($a_\mu$) is one of the long-standing puzzles of modern particle physics. After the update by the Fermilab E989 experiment in April 2021, the discrepancy between both sides lies at the 4.2-sigma level, as of the consensus made in the 2020 muon g-2 theory White Paper. The theory error is entirely dominated...
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Tim Harris (University of Milan Bicocca)27/07/2021, 07:15QCD in searches for physics beyond the Standard ModelOral presentation
We propose a method to help control cutoff effects in the short-distance contribution to integrated correlation functions, such as the hadronic vacuum polarization, using the corresponding screening correlators computed at finite temperature. The strategy is investigated with Wilson fermions at leading order, which reveals a logarithmically-enhanced lattice artifact in the short-distance...
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Miguel Teseo San Josรฉ Pรฉrez (Johannes Gutenberg Universitรคt)27/07/2021, 07:30QCD in searches for physics beyond the Standard ModelOral presentation
As present and future experiments in both the energy and precision frontiers look to identify new physics beyond the Standard Model, they require increasingly precise determinations of fundamental quantities like the electroweak couplings at various momenta. The latter can be obtained from experimental measurements or a particular reference value and the dependence on the energy. A precise,...
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Kohtaroh Miura (Helmholtz-Institut Mainz)27/07/2021, 07:45QCD in searches for physics beyond the Standard ModelOral presentation
We investigate the impact of the latest Mainz/CLS collaboration's result for the hadronic vacuum polarization (HVP) on the electroweak (EW) precision tests. The subject is closely related to the muon g-2 via the HVP. Both precision tests come under scrutiny with respect to physics Beyond the Standard Model. Our HVP calculation is used for the running electromagnetic coupling at low energy and...
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Silvano Simula (INFN - Sezione di Roma Tre), Silvano Simula (INFN)28/07/2021, 05:15QCD in searches for physics beyond the Standard ModelOral presentation
We present a comparison of existing experimental data for the radiative leptonic decays $P \to \ell \nu_\ell \gamma$, where $P=K$ or $\pi$ and $\ell = e$ or $\mu$, from the KLOE, PIBETA, E787, ISTRA+ and OKA collaborations performed in Ref. [1] using the theoretical predictions based on the recent non-perturbative determinations of the structure-dependent vector and axial-vector form factors,...
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Fionn O hOgain28/07/2021, 05:30QCD in searches for physics beyond the Standard ModelOral presentation
The $K\rightarrow\pi\ell^{+}\ell^{-}$ decay is a flavor changing neutral current process which is forbidden at tree level in the Standard Model and thus may be sensitive to potential new physics. This decay is currently being measured at the NA62 experiment in CERN and its form factor is known only through experimental results. I will discuss the ongoing lattice QCD calculation of the $q^2=0$...
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Mr Raoul Hodgson (University of Edinburgh)28/07/2021, 05:45QCD in searches for physics beyond the Standard ModelOral presentation
The rare hyperon decay $\Sigma^+ \to p \ell^+ \ell^-$ is an $s \to d$ flavour changing neutral current process that has been recently measured by the LHCb experiment with plans to improve this measurement in the future. This has prompted a need for an improved Standard Model prediction of the branching fraction of this decay.
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We present our theoretical approach and progress towards an... -
Dr Chris Bouchard (University of Glasgow )28/07/2021, 06:00QCD in searches for physics beyond the Standard ModelOral presentation
We present preliminary HPQCD results for $B \to K$ form factors $f_{0,+,T\,}(q^2)$ using the HISQ action for all valence quarks on the MILC $N_f = 2 + 1 + 1$ gauge field ensembles. The ensembles used cover five lattice spacings, include the physical pion mass, and span a range of heavy quark masses from $m_c$ to near $m_b$. Our ''heavy-HISQ'' approach allows us to map form factor heavy-quark...
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Felix Erben (University of Edinburgh)28/07/2021, 06:15QCD in searches for physics beyond the Standard ModelOral presentation
We are presenting our ongoing Lattice QCD study on $B - \bar{B}$ mixing on several RBC/UKQCD and JLQCD ensembles with 2+1 dynamical-flavour domain wall fermions, with a range of inverse lattice spacings from 1.7 to 4.5 GeV and including physical-pion-mass ensembles. We compare various different fitting strategies to extract bag parameters $B_{B_d}$ and $B_{B_s}$ both for the standard-model...
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Jian Liang28/07/2021, 06:30Oral presentation
We report our effort on calculating the neutron electric dipole moment (EDM) induced by the theta term using overlap fermions. Three 2+1-flavor RBC/UKQCD domain wall lattices with pion mass ranging from ~300 to ~500 MeV are utilized and on each gauge ensemble we use 3 partially-quenched valence pion masses. Lattice chiral fermions are essential in the calculation, which guarantees a correct...
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Rose Smail (The University of Adelaide)28/07/2021, 06:45QCD in searches for physics beyond the Standard ModelOral presentation
The nucleon tensor charge, g$_T$, is an important quantity in the search for beyond the Standard Model tensor interactions in neutron and nuclear $\beta$-decays as well as the contribution of the quark electric dipole moment (EDM) to the neutron EDM. We present results from the QCDSF, UKQCD and the CSSM collaboration for the tensor charge, $g_T$, using lattice QCD methods and the...
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Gerrit Schierholz (DESY)28/07/2021, 07:00QCD in searches for physics beyond the Standard ModelOral presentation
In QCD there is the possibility of strong CP violation arising from a nonvanishing vacuum angle $\theta$, which would result in an electric dipole moment $d_n$ of the neutron. Recently it has been shown that QCD undergoes a deconfinement phase transition at finite values of $\theta$ due to long-distance vacuum effects, which rules out any CP violation at the hadronic level, thus solving the...
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Antonino Todaro (University of Cyprus)28/07/2021, 07:15QCD in searches for physics beyond the Standard ModelOral presentation
We will present results on the neutron electric dipole moment $\vert \vec{d}_N\vert$ using an ensemble of $N_f=2+1+1$ twisted mass clover-improved fermions with lattice spacing of $a \simeq 0.08 \ {\rm fm}$ and physical pion mass ($m_{\pi} \simeq 139 \ {\rm MeV}$). The approach followed in this work is to compute the $CP$-odd electromagnetic form factor $F_3(Q^2 \to 0)$ by expanding the...
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Matthew Rizik (National Superconducting Cyclotron Laboratory)28/07/2021, 07:30QCD in searches for physics beyond the Standard ModelOral presentation
Lattice Quantum Chromodynamics (LQCD) provides the most direct probe into sources of CP-violation. These sources assume an effective form in higher-dimensional local operators built from QCD fields. Unfortunately, the operators mix with lower-dimensional operators under renormalization, introducing power divergences in the lattice spacing which inhibit a smooth continuum limit. The gradient...
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Dr Jangho Kim (Forschungszentrum Jรผlich)28/07/2021, 07:45QCD in searches for physics beyond the Standard ModelOral presentation
The quark-chromo electric dipole moment (qCEDM) operator is one of the possible beyond-the-standard-model (BSM) contributions to the electric dipole moment (EDM). Power divergences of lower dimensional operators are introduced to the qCEDM operator by operator mixing. We compute non-perturbatively the qCEDM power divergence coefficient with the gradient flow, allowing us to control the power...
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