scholarly journals Λc→Λl+νl Form Factors and Decay Rates from Lattice QCD with Physical Quark Masses

2017 ◽  
Vol 118 (8) ◽  
Author(s):  
Stefan Meinel
Keyword(s):  
Lattice Qcd ◽  
Form Factors ◽  
Decay Rates ◽  
Quark Masses

scholarly journals D → Klv semileptonic decay using lattice QCD with HISQ at physical pion masses

2018 ◽  
Vol 175 ◽  
pp. 13027 ◽  
Author(s):  
Bipasha Chakraborty ◽  
Christine Davies ◽  
Jonna Koponen ◽  
G Peter Lepage
Keyword(s):  
Standard Model ◽  
Lattice Qcd ◽  
Semileptonic Decay ◽  
Light Quark ◽  
Form Factors ◽  
New Physics ◽  
Ckm Matrix ◽  
Quark Masses ◽  
The Standard Model ◽  
Fertile Ground

he quark flavor sector of the Standard Model is a fertile ground to look for new physics effects through a unitarity test of the Cabbibo-Kobayashi-Maskawa (CKM) matrix. We present a lattice QCD calculation of the scalar and the vector form factors (over a large q2 region including q2 = 0) associated with the D→ Klv semi-leptonic decay. This calculation will then allow us to determine the central CKM matrix element, Vcs in the Standard Model, by comparing the lattice QCD results for the form factors and the experimental decay rate. This form factor calculation has been performed on the Nf = 2 + 1 + 1 MILC HISQ ensembles with the physical light quark masses.

scholarly journals Recent highlights with baryons from lattice QCD

2020 ◽  
Vol 241 ◽  
pp. 02004
Author(s):  
Colin Morningstar
Keyword(s):  
Lattice Qcd ◽  
Percent Level ◽  
Form Factors ◽  
Distribution Functions ◽  
Electromagnetic Form Factors ◽  
Parton Distribution Functions ◽  
Quark Masses ◽  
Proton Mass ◽  
Key Points

Highlights from recent computations in lattice QCD involving baryons are presented. Calcula tions of the proton mass and spin decompositions are discussed, a percent level determination of the nucleon axial coupling is described, and determinations of the proton and neutron electromagnetic form factors and light-cone parton distribution functions are outlined. Recent results applying the so-called Luscher method to meson-baryon systems are presented. Key points emphasized are that much better precision with disconnected diagrams is being achieved, incorporating multi-hadron operators is now feasible, and more and more studies are being done with physical quark masses.

scholarly journals Light meson form factors at high Q2 from lattice QCD

2018 ◽  
Vol 175 ◽  
pp. 06015 ◽  
Author(s):  
Jonna Koponen ◽  
André Zimermmane-Santos ◽  
Christine Davies ◽  
G. Peter Lepage ◽  
Andrew Lytle
Keyword(s):  
Lattice Qcd ◽  
Theoretical Calculations ◽  
Light Quark ◽  
Form Factors ◽  
Hadron Structure ◽  
Strange Quarks ◽  
Pion Scattering ◽  
Quark Masses ◽  
Systematic Uncertainties ◽  
Atomic Electrons

Measurements and theoretical calculations of meson form factors are essential for our understanding of internal hadron structure and QCD, the dynamics that bind the quarks in hadrons. The pion electromagnetic form factor has been measured at small space-like momentum transfer |q2| < 0.3 GeV2 by pion scattering from atomic electrons and at values up to 2.5 GeV2 by scattering electrons from the pion cloud around a proton. On the other hand, in the limit of very large (or infinite) Q2 = −q2, perturbation theory is applicable. This leaves a gap in the intermediate Q2 where the form factors are not known. As a part of their 12 GeV upgrade Jefferson Lab will measure pion and kaon form factors in this intermediate region, up to Q2 of 6 GeV2. This is then an ideal opportunity for lattice QCD to make an accurate prediction ahead of the experimental results. Lattice QCD provides a from-first-principles approach to calculate form factors, and the challenge here is to control the statistical and systematic uncertainties as errors grow when going to higher Q2 values. Here we report on a calculation that tests the method using an ηs meson, a ’heavy pion’ made of strange quarks, and also present preliminary results for kaon and pion form factors. We use the nf = 2 + 1 + 1 ensembles made by the MILC collaboration and Highly Improved Staggered Quarks, which allows us to obtain high statistics. The HISQ action is also designed to have small dicretisation errors. Using several light quark masses and lattice spacings allows us to control the chiral and continuum extrapolation and keep systematic errors in check.

scholarly journals D meson semileptonic form factors in Nf = 3 QCD with Möbius domain-wall quarks

2018 ◽  
Vol 175 ◽  
pp. 13007 ◽  
Author(s):  
Takashi Kaneko ◽  
Brian Colquhoun ◽  
Hidenori Fukaya ◽  
Shoji Hashimoto
Keyword(s):  
Domain Wall ◽  
Lattice Qcd ◽  
Momentum Transfer ◽  
Lattice Spacing ◽  
Light Quark ◽  
D Meson ◽  
Form Factors ◽  
Scalar Form ◽  
Charm Quarks ◽  
Quark Masses

e present our calculation of D → π and D → K semileptonic form factors in Nf = 2 + 1 lattice QCD. We simulate three lattice cutoffs a-1 ≃ 2.5, 3.6 and 4.5 GeV with pion masses as low as 230 MeV. The Möbius domain-wall action is employed for both light and charm quarks. We present our results for the vector and scalar form factors and discuss their dependence on the lattice spacing, light quark masses and momentum transfer.

scholarly journals Hadron Structure from Lattice QCD

2006 ◽  
Vol 21 (04) ◽  
pp. 720-725 ◽  
Author(s):  
◽  
J. W. Negele ◽  
B. Bistrovic ◽  
R. G. Edwards ◽  
G. Fleming ◽  
...  
Keyword(s):  
Lattice Qcd ◽  
Transition Form Factor ◽  
Form Factors ◽  
Electromagnetic Form Factors ◽  
Transition Form ◽  
Hadron Structure ◽  
Interacting Particles ◽  
Axial Charge ◽  
Charge Structure ◽  
Quark Masses

The structure of neutrons, protons, and other strongly interacting particles is now being calculated in full, unquenched lattice QCD with quark masses entering the chiral regime. This talk describes selected examples, including the nucleon axial charge, structure functions, electromagnetic form factors, the origin of the nucleon spin, the transverse structure of the nucleon, and the nucleon to Delta transition form factor.

scholarly journals Recent progress on the study of nucleon structure from lattice QCD and future perspectives

2020 ◽  
Author(s):  
Constantia Alexandrou
Keyword(s):  
Lattice Qcd ◽  
Recent Progress ◽  
Form Factors ◽  
Distribution Functions ◽  
Nucleon Structure ◽  
Electromagnetic Form Factors ◽  
Momentum Fraction ◽  
Future Perspectives ◽  
Parton Distribution Functions ◽  
Quark Masses

We review the progress achieved within the last five years in the simulations of lattice QCD, as well as in the analysis for selected quantities probing nucleon structure. In particular, we discuss results on the nucleon electromagnetic form factors, \sigmaσ-terms, the momentum fraction carried by quark in the nucleon and the helicity and transversity moments. All quantities are obtained using simulations generated with quark masses fixed to their physical values. In addition, we review the on-going effort to extract parton distribution functions (PDFs) directly from lattice QCD using the quasi-PDF approach.

scholarly journals Light-cone sum rules for proton decay

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Ulrich Haisch ◽  
Amando Hala
Keyword(s):  
Lattice Qcd ◽  
Light Cone ◽  
Sum Rules ◽  
State Of The Art ◽  
Form Factors ◽  
Baryon Number ◽  
Proton Decay ◽  
Matrix Elements ◽  
Decay Channels ◽  
Systematic Uncertainties

Abstract We estimate the form factors that parametrise the hadronic matrix elements of proton-to-pion transitions with the help of light-cone sum rules. These form factors are relevant for semi-leptonic proton decay channels induced by baryon-number violating dimension-six operators, as typically studied in the context of grand unified theories. We calculate the form factors in a kinematical regime where the momentum transfer from the proton to the pion is space-like and extrapolate our final results to the regime that is relevant for proton decay. In this way, we obtain estimates for the form factors that show agreement with the state-of-the-art calculations in lattice QCD, if systematic uncertainties are taken into account. Our work is a first step towards calculating more involved proton decay channels where lattice QCD results are not available at present.

Sign in / Sign up

Export Citation Format

Share Document