Benoît Blossier, Mariane Mangin-Brinet, José Manuel Morgado Chávez, Teseo San José
In this project, we employ the short-distance factorization to compute the distribution amplitude of the $eta_c$-meson from Lattice QCD at leading twist. We employ a set of CLS $N_f=2$ ensembles at three lattice spacings and various quark masses to extrapolate the pseudo distribution to the physical point in the isospin limit. We solve the inverse problem modeling the distribution amplitude, and we match our results to the light-cone in the $overline{text{MS}}$-scheme. We include a complete error budget, and we compare to two alternative approaches: non-relativistic QCD and Dyson-Schwinger equations, finding good agreement with the latter but not with the former.
{"title":"The $η_c$-meson leading-twist distribution amplitude","authors":"Benoît Blossier, Mariane Mangin-Brinet, José Manuel Morgado Chávez, Teseo San José","doi":"arxiv-2409.12084","DOIUrl":"https://doi.org/arxiv-2409.12084","url":null,"abstract":"In this project, we employ the short-distance factorization to compute the\u0000distribution amplitude of the $eta_c$-meson from Lattice QCD at leading twist.\u0000We employ a set of CLS $N_f=2$ ensembles at three lattice spacings and various\u0000quark masses to extrapolate the pseudo distribution to the physical point in\u0000the isospin limit. We solve the inverse problem modeling the distribution\u0000amplitude, and we match our results to the light-cone in the\u0000$overline{text{MS}}$-scheme. We include a complete error budget, and we\u0000compare to two alternative approaches: non-relativistic QCD and Dyson-Schwinger\u0000equations, finding good agreement with the latter but not with the former.","PeriodicalId":501191,"journal":{"name":"arXiv - PHYS - High Energy Physics - Lattice","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142253742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We present a general method to determine the probability that stochastic Monte Carlo data, in particular those generated in a lattice QCD calculation, would have been obtained were that data drawn from the distribution predicted by a given theoretical hypothesis. Such a probability, or p-value, is often used as an important heuristic measure of the validity of that hypothesis. The proposed method offers the benefit that it remains usable in cases where the standard Hotelling $T^2$ methods based on the conventional $chi^2$ statistic do not apply, such as for uncorrelated fits. Specifically, we analyze a general alternative to the correlated $chi^2$ statistic referred to as $q^2$, and show how to use the bootstrap as a data-driven method to determine the expected distribution of $q^2$ for a given hypothesis with minimal assumptions. This distribution can then be used to determine the p-value for a fit to the data. We also describe a bootstrap approach for quantifying the impact upon this p-value of estimating population parameters from a single ensemble of $N$ samples. The overall method is accurate up to a $1/N$ bias which we do not attempt to quantify.
我们提出了一种通用方法来确定随机蒙特卡洛数据的概率，特别是在格子 QCD 计算中生成的数据，如果这些数据来自给定理论假设所预测的分布，那么这些数据就会被得到。这种概率或 p 值经常被用作衡量假设有效性的重要启发式指标。拟议方法的好处是，在基于传统$chi^2$统计量的标准霍特林$T^2$方法不适用的情况下，例如在不相关拟合的情况下，它仍然可用。具体来说，我们分析了相关$chi^2$统计量的一般替代方法，称为$q^2$，并展示了如何使用引导法作为数据驱动方法，以最小的假设来确定给定假设下$q^2$的预期分布。我们还介绍了一种自举法，用于量化从 $N$ 样本的单一集合中估计群体参数对 p 值的影响。整个方法的精确度可达到 1/N$ 的偏差，但我们并不试图对其进行量化。
{"title":"Bootstrap-determined p-values in Lattice QCD","authors":"Norman Christ, Rajiv Eranki, Christopher Kelly","doi":"arxiv-2409.11379","DOIUrl":"https://doi.org/arxiv-2409.11379","url":null,"abstract":"We present a general method to determine the probability that stochastic\u0000Monte Carlo data, in particular those generated in a lattice QCD calculation,\u0000would have been obtained were that data drawn from the distribution predicted\u0000by a given theoretical hypothesis. Such a probability, or p-value, is often\u0000used as an important heuristic measure of the validity of that hypothesis. The\u0000proposed method offers the benefit that it remains usable in cases where the\u0000standard Hotelling $T^2$ methods based on the conventional $chi^2$ statistic\u0000do not apply, such as for uncorrelated fits. Specifically, we analyze a general\u0000alternative to the correlated $chi^2$ statistic referred to as $q^2$, and show\u0000how to use the bootstrap as a data-driven method to determine the expected\u0000distribution of $q^2$ for a given hypothesis with minimal assumptions. This\u0000distribution can then be used to determine the p-value for a fit to the data.\u0000We also describe a bootstrap approach for quantifying the impact upon this\u0000p-value of estimating population parameters from a single ensemble of $N$\u0000samples. The overall method is accurate up to a $1/N$ bias which we do not\u0000attempt to quantify.","PeriodicalId":501191,"journal":{"name":"arXiv - PHYS - High Energy Physics - Lattice","volume":"39 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142253743","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hung-Hsuan Teh, Tokiro Numasawa, Shun Okumura, Takashi Oka
We study Dirac fermions in the presence of a space-dependent chiral gauge field and thermodynamic gradients, establishing a connection to the inverse spin Hall effect. The chiral gauge field induces a chiral magnetic field, resulting in a surface Fermi arc state and a chiral Landau level state which, although is delocalized in the bulk, we show to be more robust against impurities. By applying chemical potential and temperature gradients, we achieve nonzero charge currents, with each gradient leading to distinct Fermi level dependencies, both of which have been observed in a recent experiment. Unlike the conventional mixed axial-gravitational anomaly, our currents require a noncollinear chiral magnetic field and thermodynamic gradient. We further derive low-energy transport formulas and demonstrate the importance of carefully treating the ultraviolet cutoff for understanding our lattice calculations.
{"title":"Inverse Spin Hall Effect in Nonequilibrium Dirac Systems Induced by Anomalous Flow Imbalance","authors":"Hung-Hsuan Teh, Tokiro Numasawa, Shun Okumura, Takashi Oka","doi":"arxiv-2409.09025","DOIUrl":"https://doi.org/arxiv-2409.09025","url":null,"abstract":"We study Dirac fermions in the presence of a space-dependent chiral gauge\u0000field and thermodynamic gradients, establishing a connection to the inverse\u0000spin Hall effect. The chiral gauge field induces a chiral magnetic field,\u0000resulting in a surface Fermi arc state and a chiral Landau level state which,\u0000although is delocalized in the bulk, we show to be more robust against\u0000impurities. By applying chemical potential and temperature gradients, we\u0000achieve nonzero charge currents, with each gradient leading to distinct Fermi\u0000level dependencies, both of which have been observed in a recent experiment.\u0000Unlike the conventional mixed axial-gravitational anomaly, our currents require\u0000a noncollinear chiral magnetic field and thermodynamic gradient. We further\u0000derive low-energy transport formulas and demonstrate the importance of\u0000carefully treating the ultraviolet cutoff for understanding our lattice\u0000calculations.","PeriodicalId":501191,"journal":{"name":"arXiv - PHYS - High Energy Physics - Lattice","volume":"51 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142253744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this work we calculate the renormalization of counterterms which arise in the lattice action of $N = 1$ Supersymmetric QCD (SQCD). In particular, the fine-tunings for quartic couplings are studied in detail through both continuum and lattice perturbation theory at one-loop level. For the lattice version of SQCD we make use of the Wilson gauge action for gluon fields and the Wilson fermion action for fermion fields (quarks, gluinos); for squark fields we use na"ive discretization. On the lattice, different components of squark fields mix among themselves and a total of ten quartic terms arise at the quantum level. Consequently, the renormalization conditions must take into account these effects in order to appropriately fine-tune all quartic couplings. All our results for Green's functions and renormalization factors exhibit an explicit analytic dependence on the number of colors, $N_c$, the number of flavors, $N_f$, and the gauge parameter, $alpha$, which are left unspecified. Results for the specific case $N_f=1$ are also presented, where the symmetries allow only five linearly independent quartic terms. For the calculation of the Green's functions, we consider both one-particle reducible and one-particle irreducible Feynman diagrams. Knowledge of these renormalization factors is necessary in order to relate numerical results, coming from nonperturbative studies, to ``physical'' observables.
{"title":"Supersymmetric QCD on the lattice: Fine-tuning and counterterms for the quartic couplings","authors":"Marios Costa, Herodotos Herodotou, Haralambos Panagopoulos","doi":"arxiv-2409.09089","DOIUrl":"https://doi.org/arxiv-2409.09089","url":null,"abstract":"In this work we calculate the renormalization of counterterms which arise in\u0000the lattice action of $N = 1$ Supersymmetric QCD (SQCD). In particular, the\u0000fine-tunings for quartic couplings are studied in detail through both continuum\u0000and lattice perturbation theory at one-loop level. For the lattice version of\u0000SQCD we make use of the Wilson gauge action for gluon fields and the Wilson\u0000fermion action for fermion fields (quarks, gluinos); for squark fields we use\u0000na\"ive discretization. On the lattice, different components of squark fields\u0000mix among themselves and a total of ten quartic terms arise at the quantum\u0000level. Consequently, the renormalization conditions must take into account\u0000these effects in order to appropriately fine-tune all quartic couplings. All\u0000our results for Green's functions and renormalization factors exhibit an\u0000explicit analytic dependence on the number of colors, $N_c$, the number of\u0000flavors, $N_f$, and the gauge parameter, $alpha$, which are left unspecified.\u0000Results for the specific case $N_f=1$ are also presented, where the symmetries\u0000allow only five linearly independent quartic terms. For the calculation of the\u0000Green's functions, we consider both one-particle reducible and one-particle\u0000irreducible Feynman diagrams. Knowledge of these renormalization factors is\u0000necessary in order to relate numerical results, coming from nonperturbative\u0000studies, to ``physical'' observables.","PeriodicalId":501191,"journal":{"name":"arXiv - PHYS - High Energy Physics - Lattice","volume":"15 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142253745","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Topological semimetals are some of the topological phases of matter most intensely-studied experimentally. The Weyl semimetal phase, in particular, has garned tremendous, sustained interest given fascinating signatures such as the Fermi arc surface states and the chiral anomaly, as well as the minimal requirements to protect this three-dimensional topological phase. Here, we show that thin films of Weyl semimetals (which we call quasi-(3-1)-dimensional, or q(3-1)d) generically realize finite-size topological phases distinct from 3d and 2d topological phases of established classification schemes: response signatures of the 3d bulk topology co-exist with topologically-protected, quasi-(3-2)d Fermi arc states or chiral boundary modes due to a second, previously-unidentified bulk-boundary correspondence. We show these finite-size topological semimetal phases are realized by Hamiltonians capturing the Fermiology of few-layer Van der Waals material MoTe2 in experiment. Given the broad experimental interest in few-layer Van der Waals materials and topological semimetals, our work paves the way for extensive future theoretical and experimental characterization of finite-size topological phases.
{"title":"Finite-size topological phases from semimetals","authors":"Adipta Pal, Ashley M. Cook","doi":"arxiv-2409.05842","DOIUrl":"https://doi.org/arxiv-2409.05842","url":null,"abstract":"Topological semimetals are some of the topological phases of matter most\u0000intensely-studied experimentally. The Weyl semimetal phase, in particular, has\u0000garned tremendous, sustained interest given fascinating signatures such as the\u0000Fermi arc surface states and the chiral anomaly, as well as the minimal\u0000requirements to protect this three-dimensional topological phase. Here, we show\u0000that thin films of Weyl semimetals (which we call quasi-(3-1)-dimensional, or\u0000q(3-1)d) generically realize finite-size topological phases distinct from 3d\u0000and 2d topological phases of established classification schemes: response\u0000signatures of the 3d bulk topology co-exist with topologically-protected,\u0000quasi-(3-2)d Fermi arc states or chiral boundary modes due to a second,\u0000previously-unidentified bulk-boundary correspondence. We show these finite-size\u0000topological semimetal phases are realized by Hamiltonians capturing the\u0000Fermiology of few-layer Van der Waals material MoTe2 in experiment. Given the\u0000broad experimental interest in few-layer Van der Waals materials and\u0000topological semimetals, our work paves the way for extensive future theoretical\u0000and experimental characterization of finite-size topological phases.","PeriodicalId":501191,"journal":{"name":"arXiv - PHYS - High Energy Physics - Lattice","volume":"171 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142197881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The proper flow time for the Wilson flow in calculating the topological charge, topological susceptibility, and topological charge density correlator (TCDC) using the gluonic definition is analyzed. The proper flow time for the topological charge and TCDC is determined by different methods. The proper flow time may vary depending on whether the calculation is for the topological charge, topological density, topological susceptibility, or TCDC. Specifically, the flow time identified using the matching procedure is optimal for TCDC and a good choice for the topological susceptibility. Additionally, the pseudoscalar glueball is extracted from the TCDC using the bosonic definition at the identified proper flow time for three ensembles, and the continuum mass value is obtained through continuous extrapolation.
{"title":"Proper Wilson flow time for calculating the topological charge density and the pseudoscalar glueball mass in quenched lattice QCD","authors":"Zhen Cheng, Guang-yi Xiong","doi":"arxiv-2409.02756","DOIUrl":"https://doi.org/arxiv-2409.02756","url":null,"abstract":"The proper flow time for the Wilson flow in calculating the topological\u0000charge, topological susceptibility, and topological charge density correlator\u0000(TCDC) using the gluonic definition is analyzed. The proper flow time for the\u0000topological charge and TCDC is determined by different methods. The proper flow\u0000time may vary depending on whether the calculation is for the topological\u0000charge, topological density, topological susceptibility, or TCDC. Specifically,\u0000the flow time identified using the matching procedure is optimal for TCDC and a\u0000good choice for the topological susceptibility. Additionally, the pseudoscalar\u0000glueball is extracted from the TCDC using the bosonic definition at the\u0000identified proper flow time for three ensembles, and the continuum mass value\u0000is obtained through continuous extrapolation.","PeriodicalId":501191,"journal":{"name":"arXiv - PHYS - High Energy Physics - Lattice","volume":"72 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142197882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We present progress towards the first unpolarized gluon quasi-PDF from lattice QCD using high-statistics measurement with $a approx 0.12$ fm and two valence pion masses $M_pi approx 310$ and $690$ MeV generated on $2+1+1$-flavors of HISQ ensemble by the MILC collaboration. In this study, we consider two different gluon operators, for which the hybrid-ratio renormalization matching kernels have been recently derived, and a third operator that has been used in prior pseudo-PDF studies of the gluon PDFs. We compare matrix elements for each operators for both nucleon and pseudo-scalar mesons, both pion masses, and two gauge-smearing techniques. Focusing on the more phenomenologically studied nucleon gluon PDF, we compare the ratio and hybrid-ratio renormalized matrix elements at both pion masses and both smearings to those reconstructed from the nucleon gluon PDF from the CT18 global analysis. We identify the best choice of operator to study the gluon PDF through LaMET and present the first gluon quasi-PDF under some caveats. Additionally, we explore the recent idea of Coulomb gauge fixing to improve signal at large Wilson line displacement and found it could be a major help in improving the signal of gluon matrix elements given the perturbative calculation to confirm our results. This work helps identify the best operator for studying the gluon quasi-PDF, shows higher hadron boost momentum is needed to implement hybrid-ratio renormalization reliably, and suggests the need to study more diverse set of operators with their corresponding perturbative calculations for hybrid-ratio renormalization to further gluon quasi-PDF study.
{"title":"Toward the First Gluon Parton Distribution from the LaMET","authors":"William Good, Kinza Hasan, Huey-Wen Lin","doi":"arxiv-2409.02750","DOIUrl":"https://doi.org/arxiv-2409.02750","url":null,"abstract":"We present progress towards the first unpolarized gluon quasi-PDF from\u0000lattice QCD using high-statistics measurement with $a approx 0.12$ fm and two\u0000valence pion masses $M_pi approx 310$ and $690$ MeV generated on\u0000$2+1+1$-flavors of HISQ ensemble by the MILC collaboration. In this study, we\u0000consider two different gluon operators, for which the hybrid-ratio\u0000renormalization matching kernels have been recently derived, and a third\u0000operator that has been used in prior pseudo-PDF studies of the gluon PDFs. We\u0000compare matrix elements for each operators for both nucleon and pseudo-scalar\u0000mesons, both pion masses, and two gauge-smearing techniques. Focusing on the\u0000more phenomenologically studied nucleon gluon PDF, we compare the ratio and\u0000hybrid-ratio renormalized matrix elements at both pion masses and both\u0000smearings to those reconstructed from the nucleon gluon PDF from the CT18\u0000global analysis. We identify the best choice of operator to study the gluon PDF\u0000through LaMET and present the first gluon quasi-PDF under some caveats.\u0000Additionally, we explore the recent idea of Coulomb gauge fixing to improve\u0000signal at large Wilson line displacement and found it could be a major help in\u0000improving the signal of gluon matrix elements given the perturbative\u0000calculation to confirm our results. This work helps identify the best operator\u0000for studying the gluon quasi-PDF, shows higher hadron boost momentum is needed\u0000to implement hybrid-ratio renormalization reliably, and suggests the need to\u0000study more diverse set of operators with their corresponding perturbative\u0000calculations for hybrid-ratio renormalization to further gluon quasi-PDF study.","PeriodicalId":501191,"journal":{"name":"arXiv - PHYS - High Energy Physics - Lattice","volume":"27 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142197885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
I show comparisons of the pion - pion scattering length in the isospin - two channel from simulations of of QCD with $N_c = 3$, 4 and 5 colors and $N_f = 2$ flavors of degenerate mass fermions. The scattering length varies as $1/N_c$, as expected from large $N_c$ counting arguments.
{"title":"Curve collapse for the isospin-2 pion scattering length from QCD with 3, 4, and 5 colors","authors":"Thomas DeGrand","doi":"arxiv-2409.02242","DOIUrl":"https://doi.org/arxiv-2409.02242","url":null,"abstract":"I show comparisons of the pion - pion scattering length in the isospin - two\u0000channel from simulations of of QCD with $N_c = 3$, 4 and 5 colors and $N_f = 2$\u0000flavors of degenerate mass fermions. The scattering length varies as $1/N_c$,\u0000as expected from large $N_c$ counting arguments.","PeriodicalId":501191,"journal":{"name":"arXiv - PHYS - High Energy Physics - Lattice","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142197887","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Berndt Müller, Lukas Ebner, Andreas Schäfer, Clemens Seidl, Xiaojun Yao
Nonabelian gauge theories are chaotic in the classical limit. We discuss new evidence from SU(2) lattice gauge theory that they are also chaotic at the quantum level. We also describe possible future studies aimed at discovering the consequences of this insight.
{"title":"The Nonabelian Plasma is Chaotic","authors":"Berndt Müller, Lukas Ebner, Andreas Schäfer, Clemens Seidl, Xiaojun Yao","doi":"arxiv-2409.01311","DOIUrl":"https://doi.org/arxiv-2409.01311","url":null,"abstract":"Nonabelian gauge theories are chaotic in the classical limit. We discuss new\u0000evidence from SU(2) lattice gauge theory that they are also chaotic at the\u0000quantum level. We also describe possible future studies aimed at discovering\u0000the consequences of this insight.","PeriodicalId":501191,"journal":{"name":"arXiv - PHYS - High Energy Physics - Lattice","volume":"30 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142197883","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shaun Lahert, Carleton DeTar, Aida X. El-Khadra, Steven Gottlieb, Andreas S. Kronfeld, Ruth S. Van de Water
We present results from the first lattice QCD calculation of the two-pion contributions to the light-quark connected vector-current correlation function obtained from staggered-quark operators. We employ the MILC collaboration's gauge-field ensemble with $2+1+1$ flavors of highly improved staggered sea quarks at a lattice spacing of $aapprox 0.15$ fm with a light sea-quark mass at its physical value. The two-pion contributions allow for a refined determination of the noisy long-distance tail of the vector-current correlation function, which we use to compute the light-quark connected contribution to HVP with improved statistical precision. We compare our results with traditional noise-reduction techniques used in lattice QCD calculations of the light-quark connected HVP, namely the so-called fit and bounding methods. We observe a factor of roughly three improvement in the statistical precision in the determination of the HVP contribution to the muon's anomalous magnetic moment over these approaches. We also lay the group theoretical groundwork for extending this calculation to finer lattice spacings with increased numbers of staggered two-pion taste states.
{"title":"The two-pion contribution to the hadronic vacuum polarization with staggered quarks","authors":"Shaun Lahert, Carleton DeTar, Aida X. El-Khadra, Steven Gottlieb, Andreas S. Kronfeld, Ruth S. Van de Water","doi":"arxiv-2409.00756","DOIUrl":"https://doi.org/arxiv-2409.00756","url":null,"abstract":"We present results from the first lattice QCD calculation of the two-pion\u0000contributions to the light-quark connected vector-current correlation function\u0000obtained from staggered-quark operators. We employ the MILC collaboration's\u0000gauge-field ensemble with $2+1+1$ flavors of highly improved staggered sea\u0000quarks at a lattice spacing of $aapprox 0.15$ fm with a light sea-quark mass\u0000at its physical value. The two-pion contributions allow for a refined\u0000determination of the noisy long-distance tail of the vector-current correlation\u0000function, which we use to compute the light-quark connected contribution to HVP\u0000with improved statistical precision. We compare our results with traditional\u0000noise-reduction techniques used in lattice QCD calculations of the light-quark\u0000connected HVP, namely the so-called fit and bounding methods. We observe a\u0000factor of roughly three improvement in the statistical precision in the\u0000determination of the HVP contribution to the muon's anomalous magnetic moment\u0000over these approaches. We also lay the group theoretical groundwork for\u0000extending this calculation to finer lattice spacings with increased numbers of\u0000staggered two-pion taste states.","PeriodicalId":501191,"journal":{"name":"arXiv - PHYS - High Energy Physics - Lattice","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142197888","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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