We investigate the QCD phase diagram for small values of baryon and strange quark chemical potentials from simulations at non-zero isospin chemical potential. Simulations at pure isospin chemical potential are not hindered by the sign problem and pion condensation can be observed for sufficiently large isospin chemical potentials. We study how the related phase boundary evolves with baryonic and strange chemical potentials via reweighting in quark chemical potentials and discuss our results. Furthermore, we propose and implement an alternative method to approach nonzero baryon (and strange quark) chemical potentials. This method involves simulations where physical quarks are paired with auxiliary quarks in unphysical "isospin" doublets and a decoupling of the auxiliary quarks by mass reweighting.
{"title":"Exploring the QCD phase diagram via reweighting from isospin chemical potential","authors":"B. Brandt, F. Cuteri, G. Endrődi, S. Schmalzbauer","doi":"10.22323/1.363.0189","DOIUrl":"https://doi.org/10.22323/1.363.0189","url":null,"abstract":"We investigate the QCD phase diagram for small values of baryon and strange quark chemical potentials from simulations at non-zero isospin chemical potential. Simulations at pure isospin chemical potential are not hindered by the sign problem and pion condensation can be observed for sufficiently large isospin chemical potentials. We study how the related phase boundary evolves with baryonic and strange chemical potentials via reweighting in quark chemical potentials and discuss our results. Furthermore, we propose and implement an alternative method to approach nonzero baryon (and strange quark) chemical potentials. This method involves simulations where physical quarks are paired with auxiliary quarks in unphysical \"isospin\" doublets and a decoupling of the auxiliary quarks by mass reweighting.","PeriodicalId":8440,"journal":{"name":"arXiv: High Energy Physics - Lattice","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87442739","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 gradient flow transformation can be interpreted as continuous real-space renormalization group transformation if a coarse-graining step is incorporated as part of calculating expectation values. The method allows to predict critical properties of strongly coupled systems including the renormalization group $beta$ function and anomalous dimensions at nonperturbative fixed points. In this contribution we discuss a new analysis of the continuous renormalization group $beta$ function for $N_f=2$ and $N_f=12$ fundamental flavors in SU(3) gauge theories based on this method. We follow the approach developed and tested for the $N_f=2$ system in arXiv:1910.06408. Here we present further information on the analysis, emphasizing the robustness and intuitive features of the continuous $beta$ function calculation. We also discuss the applicability of the continuous $beta$ function calculation in conformal systems, extending the possible phase diagram to include a 4-fermion interaction. The numerical analysis for $N_f=12$ uses the same set of ensembles that was generated and analyzed for the step scaling function in arXiv:1909.05842. The new analysis uses volumes with $L ge 20$ and determines the $beta$ function in the $c=0$ gradient flow renormalization scheme. The continuous $beta$ function predicts the existence of a conformal fixed point and is consistent between different operators. Although determinations of the step scaling and continuous $beta$ function use different renormalization schemes, they both predict the existence of a conformal fixed point around $g^2sim 6$.
如果在计算期望值的过程中加入粗粒度步骤，则梯度流变换可以解释为连续的实空间重整化群变换。该方法可以预测强耦合系统的关键性质，包括重整化群$beta$函数和非摄动不动点的异常维数。在这篇文章中，我们讨论了基于这种方法的SU(3)规范理论中$N_f=2$和$N_f=12$基本口味的连续重整化群$beta$函数的新分析。我们遵循arXiv:1910.06408中为$N_f=2$系统开发和测试的方法。在这里，我们提供进一步的分析信息，强调连续$beta$函数计算的鲁棒性和直观特征。我们还讨论了连续$beta$函数计算在共形系统中的适用性，扩展了可能的相图以包括4-费米子相互作用。对$N_f=12$的数值分析使用与arXiv:1909.05842中为阶跃缩放函数生成和分析的集合相同。新的分析使用$L ge 20$的体积，并确定$c=0$梯度流重整方案中的$beta$函数。连续的$beta$函数预测了保形不动点的存在，并且在不同的算子之间是一致的。虽然步进缩放和连续$beta$函数的确定使用不同的重整化方案，但它们都预测$g^2sim 6$周围存在保形不动点。
{"title":"Continuous $beta$ function for the SU(3) gauge systems with two and twelve fundamental flavors","authors":"A. Hasenfratz, O. Witzel","doi":"10.22323/1.363.0094","DOIUrl":"https://doi.org/10.22323/1.363.0094","url":null,"abstract":"The gradient flow transformation can be interpreted as continuous real-space renormalization group transformation if a coarse-graining step is incorporated as part of calculating expectation values. The method allows to predict critical properties of strongly coupled systems including the renormalization group $beta$ function and anomalous dimensions at nonperturbative fixed points. In this contribution we discuss a new analysis of the continuous renormalization group $beta$ function for $N_f=2$ and $N_f=12$ fundamental flavors in SU(3) gauge theories based on this method. We follow the approach developed and tested for the $N_f=2$ system in arXiv:1910.06408. Here we present further information on the analysis, emphasizing the robustness and intuitive features of the continuous $beta$ function calculation. We also discuss the applicability of the continuous $beta$ function calculation in conformal systems, extending the possible phase diagram to include a 4-fermion interaction. The numerical analysis for $N_f=12$ uses the same set of ensembles that was generated and analyzed for the step scaling function in arXiv:1909.05842. The new analysis uses volumes with $L ge 20$ and determines the $beta$ function in the $c=0$ gradient flow renormalization scheme. The continuous $beta$ function predicts the existence of a conformal fixed point and is consistent between different operators. Although determinations of the step scaling and continuous $beta$ function use different renormalization schemes, they both predict the existence of a conformal fixed point around $g^2sim 6$.","PeriodicalId":8440,"journal":{"name":"arXiv: High Energy Physics - Lattice","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89858230","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}
Across the finite temperature transition to the quark-gluon plasma, the QCD topological susceptibility decreases sharply. Thus in the high temperature phase the remaining topological objects (possibly calorons) form a weakly interacting dilute gas. The overlap Dirac operator, through its exact zero modes, allows one to measure the net topological charge. We show that separately the number of positively and negatively charged topological objects can also be extracted from the low end of the overlap Dirac spectrum. We find that slightly above the phase transition their number distributions are already consistent with an ideal gas of non-interacting topological objects.
{"title":"Free caloron gas in high temperature quenched QCD","authors":"R. Vig, T. Kovács","doi":"10.22323/1.363.0192","DOIUrl":"https://doi.org/10.22323/1.363.0192","url":null,"abstract":"Across the finite temperature transition to the quark-gluon plasma, the QCD topological susceptibility decreases sharply. Thus in the high temperature phase the remaining topological objects (possibly calorons) form a weakly interacting dilute gas. The overlap Dirac operator, through its exact zero modes, allows one to measure the net topological charge. We show that separately the number of positively and negatively charged topological objects can also be extracted from the low end of the overlap Dirac spectrum. We find that slightly above the phase transition their number distributions are already consistent with an ideal gas of non-interacting topological objects.","PeriodicalId":8440,"journal":{"name":"arXiv: High Energy Physics - Lattice","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76464341","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}
T. Misumi, T. Fujimori, E. Itou, M. Nitta, N. Sakai
We report the results of the lattice simulation of the ${mathbb C} P^{N-1}$ sigma model on $S_{s}^{1}$(large) $times$ $S_{tau}^{1}$(small). We take a sufficiently large ratio of the circumferences to approximate the model on ${mathbb R} times S^1$. For periodic boundary condition imposed in the $S_{tau}^{1}$ direction, we show that the expectation value of the Polyakov loop undergoes a deconfinement crossover as the compactified circumference is decreased, where the peak of the associated susceptibility gets sharper for larger $N$. For ${mathbb Z}_{N}$ twisted boundary condition, we find that, even at relatively high $beta$ (small circumference), the regular $N$-sided polygon-shaped distributions of Polyakov loop leads to small expectation values of Polyakov loop, which implies unbroken ${mathbb Z}_{N}$ symmetry if sufficient statistics and large volumes are adopted. We also argue the existence of fractional instantons and bions by investigating the dependence of the Polyakov loop on $S_{s}^{1}$ direction, which causes transition between ${mathbb Z}_{N}$ vacua.
我们在$S_{s}^{1}$(大)$times$$S_{tau}^{1}$(小)上报告了${mathbb C} P^{N-1}$ sigma模型的晶格模拟结果。我们取足够大的周长比例来近似${mathbb R} times S^1$上的模型。对于施加于$S_{tau}^{1}$方向的周期边界条件，我们表明，随着紧化周长的减小，Polyakov环的期望值经历了一个去定义交叉，其中相关磁化率的峰值随着$N$的增大而变得更加明显。对于${mathbb Z}_{N}$扭曲边界条件，我们发现，即使在较高的$beta$(小周长)下，Polyakov环的规则的$N$边多边形分布导致Polyakov环的期望值较小，这意味着如果采用足够的统计量和大体积，则不破坏${mathbb Z}_{N}$对称性。我们还通过研究Polyakov环对$S_{s}^{1}$方向的依赖，论证了分数瞬子和十亿子的存在性，这导致了${mathbb Z}_{N}$真空之间的跃迁。
{"title":"Lattice study on the twisted ${mathbb C} P^{N-1}$ models on ${mathbb R} times S^1$","authors":"T. Misumi, T. Fujimori, E. Itou, M. Nitta, N. Sakai","doi":"10.22323/1.363.0015","DOIUrl":"https://doi.org/10.22323/1.363.0015","url":null,"abstract":"We report the results of the lattice simulation of the ${mathbb C} P^{N-1}$ sigma model \u0000on $S_{s}^{1}$(large) $times$ $S_{tau}^{1}$(small). We take a sufficiently large ratio of the circumferences to approximate the model on ${mathbb R} times S^1$. For periodic boundary condition imposed in the $S_{tau}^{1}$ direction, we show that the expectation value of the Polyakov loop undergoes a deconfinement crossover as the compactified circumference is decreased, where the peak of the associated susceptibility gets sharper for larger $N$. For ${mathbb Z}_{N}$ twisted boundary condition, we find that, even at relatively high $beta$ (small circumference), the regular $N$-sided polygon-shaped distributions of Polyakov loop leads to small expectation values of Polyakov loop, which implies unbroken ${mathbb Z}_{N}$ symmetry if sufficient statistics and large volumes are adopted. We also argue the existence of fractional instantons and bions by investigating the dependence of the Polyakov loop on $S_{s}^{1}$ direction, which causes transition between ${mathbb Z}_{N}$ vacua.","PeriodicalId":8440,"journal":{"name":"arXiv: High Energy Physics - Lattice","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88210211","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 calculate correlation functions of two local operators within the nucleon carrying momentum. We resolve their dependence on the spatial distance of the currents. This is carried out for all Wick contractions, taking into account several operator insertion types. The resulting four-point functions can be related to parton distribution functions as well as to Mellin moments of double parton distributions. For the latter, we analyze their quark spin and flavor dependency. In this first study, we employ an $N_F = 2 + 1$ CLS ensemble on a $96 times 32^3$ lattice with lattice spacing $a = 0.0856 mathrm{fm}$ and the pseudoscalar masses $m_pi = 355 mathrm{MeV}$ and $m_K = 441 mathrm{MeV}$.
{"title":"Two-current correlations and DPDs for the nucleon on the lattice","authors":"C. Zimmermann","doi":"10.22323/1.363.0040","DOIUrl":"https://doi.org/10.22323/1.363.0040","url":null,"abstract":"We calculate correlation functions of two local operators within the nucleon carrying momentum. We resolve their dependence on the spatial distance of the currents. This is carried out for all Wick contractions, taking into account several operator insertion types. The resulting four-point functions can be related to parton distribution functions as well as to Mellin moments of double parton distributions. For the latter, we analyze their quark spin and flavor dependency. In this first study, we employ an $N_F = 2 + 1$ CLS ensemble on a $96 times 32^3$ lattice with lattice spacing $a = 0.0856 mathrm{fm}$ and the pseudoscalar masses $m_pi = 355 mathrm{MeV}$ and $m_K = 441 mathrm{MeV}$.","PeriodicalId":8440,"journal":{"name":"arXiv: High Energy Physics - Lattice","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83608937","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 report on our calculation of the interglueball potentials in SU(2), SU(3), and SU(4) lattice Yang-Mills theories using the indirect (so-called HAL QCD) method. We use the cluster decomposition error reduction technique to improve the statistical accuracy of the glueball correlators. After calculating the glueball scattering cross section in SU(2) Yang-Mills theory and combining with the observational data of the dark matter mass distributions, we derive the lower limit on the scale parameter.
{"title":"Interglueball potential in SU(N$_c$) lattice gauge theory","authors":"N. Yamanaka, H. Iida, A. Nakamura, M. Wakayama","doi":"10.22323/1.363.0013","DOIUrl":"https://doi.org/10.22323/1.363.0013","url":null,"abstract":"We report on our calculation of the interglueball potentials in SU(2), SU(3), and SU(4) lattice Yang-Mills theories using the indirect (so-called HAL QCD) method. We use the cluster decomposition error reduction technique to improve the statistical accuracy of the glueball correlators. After calculating the glueball scattering cross section in SU(2) Yang-Mills theory and combining with the observational data of the dark matter mass distributions, we derive the lower limit on the scale parameter.","PeriodicalId":8440,"journal":{"name":"arXiv: High Energy Physics - Lattice","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86537862","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}
J. Frison, A. Bussone, G. Herdo'iza, C. Peña, Jos'e 'Angel Romero, Javier Ugarrio
The first phase of a heavy quark program based on twisted mass valence quarks has been presented at last years's lattice conference. The CLS $N_f=2+1$ ensembles were used for their fine lattice spacing, while twisting the masses is expected to reduce discretisation errors even further and allow for a fully relativistic calculation. We present our strategy and preliminary results on three point functions, corresponding to $Dto K$ and $Dtopi$ semileptonic decays. The form factors for $m_u=m_d=m_s$ quark masses obtained as a first step are shown here to be at the percent level in statistical precision at $q^2=0$.
{"title":"Heavy semileptonics with a fully relativistic mixed action","authors":"J. Frison, A. Bussone, G. Herdo'iza, C. Peña, Jos'e 'Angel Romero, Javier Ugarrio","doi":"10.22323/1.363.0234","DOIUrl":"https://doi.org/10.22323/1.363.0234","url":null,"abstract":"The first phase of a heavy quark program based on twisted mass valence quarks has been presented at last years's lattice conference. The CLS $N_f=2+1$ ensembles were used for their fine lattice spacing, while twisting the masses is expected to reduce discretisation errors even further and allow for a fully relativistic calculation. We present our strategy and preliminary results on three point functions, corresponding to $Dto K$ and $Dtopi$ semileptonic decays. The form factors for $m_u=m_d=m_s$ quark masses obtained as a first step are shown here to be at the percent level in statistical precision at $q^2=0$.","PeriodicalId":8440,"journal":{"name":"arXiv: High Energy Physics - Lattice","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79806989","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}
E. Bennett, D. Hong, Jong-Wan Lee, C. Lin, B. Lucini, M. Piai, Davide Vadacchino
We calculate the meson spectrum of the Sp(4) lattice gauge theory coupled to two fundamental flavours of dynamical Dirac fermions. We focus on some of the lightest (flavoured) spin-0 and spin-1 states. This theory provides an ultraviolet completion for composite Higgs models based upon the SU(4)/Sp(4) coset. We analyse the strongly coupled dynamics in isolation, without explicit coupling to the standard model. We carry out continuum extrapolations using dynamical ensembles generated at five different values of bare lattice coupling, and for several values of the bare fermion mass. We fit the resulting meson masses and decay constants to a low-energy effective field theory built along the ideas of hidden local symmetry. We also compare our results to those of other closely related lattice gauge theories, which have matter content consisting of two fundamental Dirac flavours.
{"title":"Meson spectrum of Sp(4) lattice gauge theory with two fundamental Dirac fermions","authors":"E. Bennett, D. Hong, Jong-Wan Lee, C. Lin, B. Lucini, M. Piai, Davide Vadacchino","doi":"10.22323/1.363.0054","DOIUrl":"https://doi.org/10.22323/1.363.0054","url":null,"abstract":"We calculate the meson spectrum of the Sp(4) lattice gauge theory coupled to two fundamental flavours of dynamical Dirac fermions. We focus on some of the lightest (flavoured) spin-0 and spin-1 states. This theory provides an ultraviolet completion for composite Higgs models based upon the SU(4)/Sp(4) coset. We analyse the strongly coupled dynamics in isolation, without explicit coupling to the standard model. We carry out continuum extrapolations using dynamical ensembles generated at five different values of bare lattice coupling, and for several values of the bare fermion mass. We fit the resulting meson masses and decay constants to a low-energy effective field theory built along the ideas of hidden local symmetry. We also compare our results to those of other closely related lattice gauge theories, which have matter content consisting of two fundamental Dirac flavours.","PeriodicalId":8440,"journal":{"name":"arXiv: High Energy Physics - Lattice","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87699784","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}
Systematics in nucleon isovector vector, $g_V$, and axialvector, $g_A$, charges calculated on a 2+1-flavor dynamical domain-wall-fermions (DWF) ensemble at physical mass jointly generated by RIKEN-BNL-Columbia (RBC) and UKQCD Collaborations with lattice cut off of 1.730(4) GeV, are analyzed. Both are calculated with about a percent or less statistical errors. A few standard-deviation systematics seen in vector charge is consistent with possible $O(a^2)$ discretization error through small excited-state contamination. Axialvector charge is found with three to nine standard-deviation systematic deficit, compared with experiments, depending on calculation methods.
{"title":"Nucleon isovector charges from physical mass domain-wall QCD.","authors":"S. Ohta","doi":"10.22323/1.363.0051","DOIUrl":"https://doi.org/10.22323/1.363.0051","url":null,"abstract":"Systematics in nucleon isovector vector, $g_V$, and axialvector, $g_A$, charges calculated on a 2+1-flavor dynamical domain-wall-fermions (DWF) ensemble at physical mass jointly generated by RIKEN-BNL-Columbia (RBC) and UKQCD Collaborations with lattice cut off of 1.730(4) GeV, are analyzed. Both are calculated with about a percent or less statistical errors. A few standard-deviation systematics seen in vector charge is consistent with possible $O(a^2)$ discretization error through small excited-state contamination. Axialvector charge is found with three to nine standard-deviation systematic deficit, compared with experiments, depending on calculation methods.","PeriodicalId":8440,"journal":{"name":"arXiv: High Energy Physics - Lattice","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74123845","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}
Pub Date : 2019-10-25DOI: 10.1103/PHYSREVD.102.054506
Yu Meng, Chuan Liu, Ke-Long Zhang
Three photon decay rate of $J/psi$ is studied using two $N_f=2$ twisted mass gauge ensembles with lattice spacings $asimeq 0.085$ fm (I) and $0.067$ fm(II). Using a new method, only the correlation functions directly related to the physical decay width are computed with all polarizations of the initial and final states summed over. Our results for such rare decay on the two ensembles are: $mathcal{B}_{I,II}(J/psirightarrow 3gamma)=(1.614 pm 0.016 pm 0.261)times 10^{-5},(1.809 pm 0.051 pm 0.295)times 10^{-5}$ where the first errors are statistical and the second are estimates from systematics. We also propose a method to analyze the Dalitz plot of the corresponding process based on the lattice data which can provide direct information for the experiments.
{"title":"Three photon decay of \u0000J/ψ\u0000 from lattice QCD","authors":"Yu Meng, Chuan Liu, Ke-Long Zhang","doi":"10.1103/PHYSREVD.102.054506","DOIUrl":"https://doi.org/10.1103/PHYSREVD.102.054506","url":null,"abstract":"Three photon decay rate of $J/psi$ is studied using two $N_f=2$ twisted mass gauge ensembles with lattice spacings $asimeq 0.085$ fm (I) and $0.067$ fm(II). Using a new method, only the correlation functions directly related to the physical decay width are computed with all polarizations of the initial and final states summed over. Our results for such rare decay on the two ensembles are: $mathcal{B}_{I,II}(J/psirightarrow 3gamma)=(1.614 pm 0.016 pm 0.261)times 10^{-5},(1.809 pm 0.051 pm 0.295)times 10^{-5}$ where the first errors are statistical and the second are estimates from systematics. We also propose a method to analyze the Dalitz plot of the corresponding process based on the lattice data which can provide direct information for the experiments.","PeriodicalId":8440,"journal":{"name":"arXiv: High Energy Physics - Lattice","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81684860","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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