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Proceedings of The 9th International workshop on Chiral Dynamics — PoS(CD2018)最新文献

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Dispersive techniques for low-energy QCD: Pion-pion and pion-kaon scattering 低能QCD的色散技术:介子-介子和介子-介子散射
Proceedings of The 9th International workshop on Chiral Dynamics — PoS(CD2018) Pub Date : 2020-02-28 DOI: 10.22323/1.317.0004
J. R. D. Elvira
{"title":"Dispersive techniques for low-energy QCD: Pion-pion and pion-kaon scattering","authors":"J. R. D. Elvira","doi":"10.22323/1.317.0004","DOIUrl":"https://doi.org/10.22323/1.317.0004","url":null,"abstract":"A good understanding of strong interactions at low energies is key in the precision frontier of Particle and Hadron Physics, since most hadronic observables end up in final states involving pions and kaons, the lightest mesons in the Hadron Spectrum. In particular, the pion–pion and pion–kaon scattering lengths are the lowest energy observables for these interactions, and hence a fundamental quantity for understanding hadron interaction at low energies. In this talk we review the current status of their determination. After discussing the predictions expected from chiral symmetry at different orders in the chiral expansion, we review current experimental and lattice determinations. We then focus on the dispersive determination of pion-pion and pion-kaon interactions, based on the analysis of Roy and Roy-Steiner equation, and continue discussing in detail the current tension between the chiral symmetry and dispersive predicition for the pion- kaon scattering lenthgs. We finish this talk providing an explanation of this disagreement.","PeriodicalId":445979,"journal":{"name":"Proceedings of The 9th International workshop on Chiral Dynamics — PoS(CD2018)","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117120394","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}
引用次数: 0
Neutron-deuteron scattering (chiral potentials & regulator dependence) 中子-氘核散射(手性势和调节器依赖)
Proceedings of The 9th International workshop on Chiral Dynamics — PoS(CD2018) Pub Date : 2020-02-28 DOI: 10.22323/1.317.0109
R. Skibiński, J. Golak, V. Soloviov, K. Topolnicki, V. Urbanevych, Y. Volkotrub, H. Witała
{"title":"Neutron-deuteron scattering (chiral potentials & regulator dependence)","authors":"R. Skibiński, J. Golak, V. Soloviov, K. Topolnicki, V. Urbanevych, Y. Volkotrub, H. Witała","doi":"10.22323/1.317.0109","DOIUrl":"https://doi.org/10.22323/1.317.0109","url":null,"abstract":"The predictions for the differential cross section and the deuteron tensor analyzing power T$_{22}$ in nucleon-deuteron elastic scattering based on two chiral models of the nucleon-nucleon interaction are presented and compared with each other and with the data. The recent models at the fifth order of the chiral expansion from the Moscow(Idaho)-Salamanca group and from the Bochum group are used. At the energy of the incoming nucleon E=65 MeV both potentials yield similar data descriptions, however the differences between both models become more significant at E=200 MeV. At the latter energy the dependence of predictions on the used value of the regularization parameter becomes important. In particular, this cutoff dependence is much smaller in the case of the semilocally momentum space regularized potential from the Bochum group.","PeriodicalId":445979,"journal":{"name":"Proceedings of The 9th International workshop on Chiral Dynamics — PoS(CD2018)","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127134742","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}
引用次数: 0
Two-Photon exchange in elastic lepton-proton scattering 弹性轻子-质子散射中的双光子交换
Proceedings of The 9th International workshop on Chiral Dynamics — PoS(CD2018) Pub Date : 2020-02-28 DOI: 10.22323/1.317.0022
J. Bernauer
{"title":"Two-Photon exchange in elastic lepton-proton scattering","authors":"J. Bernauer","doi":"10.22323/1.317.0022","DOIUrl":"https://doi.org/10.22323/1.317.0022","url":null,"abstract":"The proton elastic form factor ratio can be directly accessed via measurements exploiting polarization degrees of freedom. Compared to the ratio formed with the Rosenbluth-separated form factors from unpolarized measurements Rosenbluth, they show a different trend growing with Q2. The proposed explanation is two-photon exchange, which has recently been measured in three precision experiments. From these new data, a hard two-photon exchange effect at the couple-of-percent level can be extracted, in significant disagreement from theoretical calculation. Theory at larger momentum transfer remains untested, as well as the accuracy of the descriptions at lowest Q2, relevant for the extraction of the proton’s rms. charge and magnetic radii.","PeriodicalId":445979,"journal":{"name":"Proceedings of The 9th International workshop on Chiral Dynamics — PoS(CD2018)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129133630","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}
引用次数: 0
Isospin-breaking corrections to the muon magnetic anomaly in Lattice QCD 晶格QCD中介子磁异常的同位旋破缺修正
Proceedings of The 9th International workshop on Chiral Dynamics — PoS(CD2018) Pub Date : 2019-09-04 DOI: 10.22323/1.317.0063
D. Giusti, V. Lubicz, G. Martinelli, F. Sanfilippo, S. Simula
{"title":"Isospin-breaking corrections to the muon magnetic anomaly in Lattice QCD","authors":"D. Giusti, V. Lubicz, G. Martinelli, F. Sanfilippo, S. Simula","doi":"10.22323/1.317.0063","DOIUrl":"https://doi.org/10.22323/1.317.0063","url":null,"abstract":"In this contribution we present a lattice calculation of the leading-order electromagnetic and strong isospin-breaking (IB) corrections to the quark-connected hadronic-vacuum-polarization (HVP) contribution to the anomalous magnetic moment of the muon. The results are obtained adopting the RM123 approach in the quenched-QED approximation and using the QCD gauge configurations generated by the ETM Collaboration with $N_f = 2+1+1$ dynamical quarks, at three values of the lattice spacing ($a simeq 0.062, 0.082, 0.089$ fm), at several lattice volumes and with pion masses between $simeq 210$ and $simeq 450$ MeV. After the extrapolations to the physical pion mass and to the continuum and infinite-volume limits the contributions of the light, strange and charm quarks are respectively equal to $delta a_mu^{rm HVP}(ud) = 7.1 ~ (2.5) cdot 10^{-10}$, $delta a_mu^{rm HVP}(s) = -0.0053 ~ (33) cdot 10^{-10}$ and $delta a_mu^{rm HVP}(c) = 0.0182 ~ (36) cdot 10^{-10}$. At leading order in $alpha_{em}$ and $(m_d - m_u) / Lambda_{QCD}$ we obtain $delta a_mu^{rm HVP}(udsc) = 7.1 ~ (2.9) cdot 10^{-10}$, which is currently the most accurate determination of the IB corrections to $a_mu^{rm HVP}$.","PeriodicalId":445979,"journal":{"name":"Proceedings of The 9th International workshop on Chiral Dynamics — PoS(CD2018)","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130790066","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}
引用次数: 2
Electroweak Current Operators in Chiral Effective Field Theory 手性有效场论中的弱电流算子
Proceedings of The 9th International workshop on Chiral Dynamics — PoS(CD2018) Pub Date : 2019-08-05 DOI: 10.22323/1.317.0098
H. Krebs
{"title":"Electroweak Current Operators in Chiral Effective Field Theory","authors":"H. Krebs","doi":"10.22323/1.317.0098","DOIUrl":"https://doi.org/10.22323/1.317.0098","url":null,"abstract":"In this proceeding I briefly review current status of the construction of nuclear electro-weak currents within chiral effective field theory. I show that gauge and chiral symmetry requirements lead to the well-known continuity equations for the current and charge operators which, however, get modified at higher orders. Regularization of the current will be also discussed. I demonstrate that implementation of a cutoff regulator in a naive way leads to violation of chiral symmetry. To respect the underlying symmetries I propose to use higher derivative regularization in the nuclear forces and currents.","PeriodicalId":445979,"journal":{"name":"Proceedings of The 9th International workshop on Chiral Dynamics — PoS(CD2018)","volume":"2021 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125292230","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}
引用次数: 4
On the Cottingham formula and the electromagnetic contribution to the proton-neutron mass splitting 论科廷厄姆公式和电磁对质子-中子质量分裂的贡献
Proceedings of The 9th International workshop on Chiral Dynamics — PoS(CD2018) Pub Date : 2019-07-11 DOI: 10.22323/1.317.0045
A. Walker-Loud
{"title":"On the Cottingham formula and the electromagnetic contribution to the proton-neutron mass splitting","authors":"A. Walker-Loud","doi":"10.22323/1.317.0045","DOIUrl":"https://doi.org/10.22323/1.317.0045","url":null,"abstract":"The excess mass of the neutron over the proton arises from two sources within the Standard Model, electromagnetism and the splitting of the down and up quark masses. The Cottingham Formula provides a means of determining the QED corrections from the forward Compton Amplitude, but this is challenged by the need for a subtraction function and the mixing of the QED and QCD (electro-weak) effects. I review the present understanding of the Cottingham Formula, including a discussion on the development of the formula, its renormalization which induces the mixing of QED and QCD effects, and the necessary modeling of the subtraction function that must be done to arrive a numerical prediction. I summarize the Regge Model originally proposed by Gasser and Leutwyler and I also review the proposed model by Walker-Loud, Carlson and Miller, which is an interpolation function between the low and high $Q^2$ regimes, both of which are anchored by rigorous theoretical underpinnings, for which I argue a more reliable theoretical uncertainty estimate can be obtained.","PeriodicalId":445979,"journal":{"name":"Proceedings of The 9th International workshop on Chiral Dynamics — PoS(CD2018)","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121419481","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}
引用次数: 4
Coarse graining hadronic scattering 粗粒强子散射
Proceedings of The 9th International workshop on Chiral Dynamics — PoS(CD2018) Pub Date : 2019-06-26 DOI: 10.22323/1.317.0082
E. Arriola, J. R. D. Elvira
{"title":"Coarse graining hadronic scattering","authors":"E. Arriola, J. R. D. Elvira","doi":"10.22323/1.317.0082","DOIUrl":"https://doi.org/10.22323/1.317.0082","url":null,"abstract":"We show that it makes sense to coarse grain hadronic interactions such as $pipi$ and $pi N$ reactions following previous work on NN scattering. Moreover, if the interaction is taken to be given by chiral dynamics at long distances above a given value $r > r_c$ larger than the elementary radii of the interaction hadrons the unknown short distance region $r< r_c$ is characterized by a {it finite} number of fitting parameters. This number of independent parameters needed for a presumably complete description of scattering data for a CM energy below $sqrt{s}$ has been found to be given by $N_{rm Par} = N_S times N_I times (p r_c )^2 /2 $ with $N_S$ and $N_I$ the number of spin and isospin channels, and $p$ the CM momentum respectively. Therefore, for an experiment (or sets of experiments) with a total number of data $N_{rm Dat}$ the number of degrees of freedom involved in a $chi^2$-fit is given by $nu = N_{rm Dat}-N_{rm Par}$ and confidence levels can be obtained accordingly by standard means. Namely a $1 sigma$ confidence level corresponds to $chi_{rm min}^2/nu in (1- sqrt{2/nu},1+sqrt{2/nu})$. We discuss the approach for $pipi$ and $pi N$ with an eye put on a data selection program and the eventual validation of chiral symmetry.","PeriodicalId":445979,"journal":{"name":"Proceedings of The 9th International workshop on Chiral Dynamics — PoS(CD2018)","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116879803","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}
引用次数: 1
Pseudoscalar flavor singlet mesons from lattice QCD 晶格QCD中的伪标量味单重介子
Proceedings of The 9th International workshop on Chiral Dynamics — PoS(CD2018) Pub Date : 2019-05-20 DOI: 10.22323/1.317.0077
K. Ottnad
{"title":"Pseudoscalar flavor singlet mesons from lattice QCD","authors":"K. Ottnad","doi":"10.22323/1.317.0077","DOIUrl":"https://doi.org/10.22323/1.317.0077","url":null,"abstract":"We investigate the masses and mixing of $eta$, $eta'$ mesons in the framework of twisted mass lattice QCD with $N_f=2+1+1$ dynamical quark flavors. For the first time we perform a controlled chiral and continuum extrapolation to obtain physical results. To this end, we have analyzed 17 gauge ensembles with pion masses ranging from $220,mathrm{MeV}$ to $500,mathrm{MeV}$ and at three values of the lattice spacing. This calculation became feasible through the application of a powerful variance reduction technique for the computation of quark-disconnected diagrams together with several improvements in the final analysis, including a correction of the relevant correlation functions for residual topological finite volume effects. We obtain physical results for the masses $M_{eta}=557(11)_mathrm{stat}(03)_{chimathrm{PT}},mathrm{MeV}$ and $M_{eta'}=911(64)_mathrm{stat}(03)_{chimathrm{PT}},mathrm{MeV}$, as well as the mixing angle in the quark flavor basis $phi=38.8(2.2)_mathrm{stat}(2.4)_{chimathrm{PT}}^circ$, in excellent agreement with other results from phenomenology. Similarly, for the physical values of the decay constant parameters we find $f_l=125(5)_mathrm{stat}(6)_{chimathrm{PT}},mathrm{MeV}$ and $f_s=178(4)_mathrm{stat}(1)_{chimathrm{PT}},mathrm{MeV}$. Finally, we present a test of the Veneziano Witten formula using our lattice data.","PeriodicalId":445979,"journal":{"name":"Proceedings of The 9th International workshop on Chiral Dynamics — PoS(CD2018)","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129902100","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}
引用次数: 3
On the convergence of chiral expansions for charmed meson masses in the up, down and strange quark masses 上、下、奇夸克质量中粲介子质量手性展开的收敛性
Proceedings of The 9th International workshop on Chiral Dynamics — PoS(CD2018) Pub Date : 2019-04-03 DOI: 10.22323/1.317.0075
M. Lutz, Xiao Guo, Yonggoo Heo
{"title":"On the convergence of chiral expansions for charmed meson masses in the up, down and strange quark masses","authors":"M. Lutz, Xiao Guo, Yonggoo Heo","doi":"10.22323/1.317.0075","DOIUrl":"https://doi.org/10.22323/1.317.0075","url":null,"abstract":"We discuss the convergence properties of chiral expansions for the pseudoscalar and vector charmed meson masses based on the chiral SU(3) Lagrangian. Conventional expansion strategies as formulated in terms of bare meson masses are shown to suffer from poor convergence properties. This changes once the expansion is set up in terms of on-shell masses. We find a rapid convergence of the chiral expansion from vanishing quark masses up to physical values of the strange quark mass in this case. Detailed results are presented at the one-loop level for the D-meson and D^*-meson masses. It is emphasized that our results do not depend on the renormalization scale. An approximation hierarchy for the chiral Ward identities of QCD is obtained that keeps the proper form of low-energy branch points and cuts as they are implied by the use of on-shell masses. Given such a scheme we analyzed the charmed meson masses as available on various QCD lattice ensembles. In terms of the determined low-energy constants we consider the coupled-channel interactions of the Goldstone bosons with open-charm mesons. For the isospin violating hadronic decay width of the D_{s0}^*(2317) we predict the range (104-116) keV.","PeriodicalId":445979,"journal":{"name":"Proceedings of The 9th International workshop on Chiral Dynamics — PoS(CD2018)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131256785","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}
引用次数: 0
The muong−2: a brief overview of hadronic crosssection data muong−2:强子截面数据的简要概述
Proceedings of The 9th International workshop on Chiral Dynamics — PoS(CD2018) Pub Date : 2019-03-22 DOI: 10.22323/1.317.0070
A. Keshavarzi
{"title":"The muong−2: a brief overview of hadronic crosssection data","authors":"A. Keshavarzi","doi":"10.22323/1.317.0070","DOIUrl":"https://doi.org/10.22323/1.317.0070","url":null,"abstract":"The hadronic vacuum polarisation contributions to the anomalous magnetic moment of the muon, $a_{mu}^{rm had, VP}$ are evaluated dispersively via a combination of experimentally measured $e^+e^-rightarrow {rm hadrons}$ cross section data. Many experiments have dedicated programmes to precisely measure these final states, meaning that a vast amount of data is now available and that, in some cases, overall precision has reached the sub-percent level. However, data tensions are evident between measurements of the same hadronic channels from different experiments, which reduces the overall quality of the data combinations used to determine $a_{mu}^{rm had, , VP}$. The inclusion of these data in the KNT18 analysis results in $a_{mu}^{rm had, , LO , VP} = (693.26 pm 2.46)times 10^{-10}$ and $a_{mu}^{rm had, , NLO , VP} = (-9.82 pm 0.04)times 10^{-10}$. The corresponding new estimate for the Standard Model prediction is found to be $a_{mu}^{rm SM} = (11 659 182.04 pm 3.56) times 10^{-10}$, which is $3.7sigma$ below the current experimental measurement.","PeriodicalId":445979,"journal":{"name":"Proceedings of The 9th International workshop on Chiral Dynamics — PoS(CD2018)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132081340","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}
引用次数: 1
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