scholarly journals B PHYSICS ON THE LATTICE: PRESENT AND FUTURE

2006 ◽  
Vol 21 (15) ◽  
pp. 1167-1182 ◽  
Author(s):  
MATTHEW WINGATE
Keyword(s):  
Lattice Qcd ◽  
Light Quark ◽  
Mass Difference ◽  
Current Status ◽  
Recent Measurement ◽  
Experimental Measurements ◽  
Decay Channels ◽  
Flavor Changing ◽  
Lattice Calculations ◽  
Light Quark Mass

Recent experimental measurements and lattice QCD calculations are now reaching the precision (and accuracy) needed to over-constrain the CKM parameters [Formula: see text] and [Formula: see text]. In this brief review, we discuss the current status of lattice QCD calculations needed to connect the experimental measurements of B meson properties to quark flavor-changing parameters. Special attention is given to B→πℓν, which is becoming a competitive way to determine |Vub|, and to [Formula: see text] mixings, which now include reliable extrapolation to the physical light quark mass. The combination of the recent measurement of the Bs mass difference and current lattice calculations dramatically reduces the uncertainty in |Vtd|. We present an outlook for reducing dominant lattice QCD uncertainties entering CKM fits and remark on lattice calculations for other decay channels.

scholarly journals Isospin-1/2 Dπ scattering and the lightest $$ {D}_0^{\ast } $$ resonance from lattice QCD

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Luke Gayer ◽  
Nicolas Lang ◽  
Sinéad M. Ryan ◽  
David Tims ◽  
Christopher E. Thomas ◽  
...  
Keyword(s):  
Scattering Amplitudes ◽  
Lattice Qcd ◽  
Quark Mass ◽  
Light Quark ◽  
Energy Levels ◽  
Experimental Result ◽  
Infinite Volume ◽  
Resonance Pole ◽  
Strongly Coupled ◽  
Light Quark Mass

Abstract Isospin-1/2 Dπ scattering amplitudes are computed using lattice QCD, working in a single volume of approximately (3.6 fm)3 and with a light quark mass corresponding to mπ ≈ 239 MeV. The spectrum of the elastic Dπ energy region is computed yielding 20 energy levels. Using the Lüscher finite-volume quantisation condition, these energies are translated into constraints on the infinite-volume scattering amplitudes and hence enable us to map out the energy dependence of elastic Dπ scattering. By analytically continuing a range of scattering amplitudes, a $$ {D}_0^{\ast } $$ D 0 ∗ resonance pole is consistently found strongly coupled to the S-wave Dπ channel, with a mass m ≈ 2200 MeV and a width Γ ≈ 400 MeV. Combined with earlier work investigating the $$ {D}_{s0}^{\ast } $$ D s 0 ∗ , and $$ {D}_0^{\ast } $$ D 0 ∗ with heavier light quarks, similar couplings between each of these scalar states and their relevant meson-meson scattering channels are determined. The mass of the $$ {D}_0^{\ast } $$ D 0 ∗ is consistently found well below that of the $$ {D}_{s0}^{\ast } $$ D s 0 ∗ , in contrast to the currently reported experimental result.

PHYSICS ISSUES IN η′ DECAYS

2005 ◽  
Vol 20 (02n03) ◽  
pp. 532-535 ◽  
Author(s):  
MAGNUS WOLKE
Keyword(s):  
Radiative Decay ◽  
Light Quark ◽  
Mass Difference ◽  
Experimental Information ◽  
Hadronic Decays ◽  
Fundamental Physics ◽  
Leptonic Decays ◽  
Light Quark Mass ◽  
Isospin Symmetry Breaking ◽  
Shed Light

Studies of hadronic, radiative, and (semi–)leptonic decays of the η′ allow to shed light on a broad field of fundamental physics questions. Isospin symmetry breaking decays provide a well-suited tool to extract the light quark mass difference. Differential distributions in hadronic decays both test predictions obtained within ChPT approaches, and enclose information on the scalar meson sector. Precision measurements on radiative decay widths will constrain pseudoscalar mixing, the manifestation of QCD anomalies, and the structure of the η′. The latter is also subject of investigation in semileptonic decays probing the η′ transition form factor. The presently available experimental information is reviewed, and prospects for η′ decay physics with WASA at COSY are presented.

τ → δν decay induced by light quark mass difference

1982 ◽  
Vol 115 (3) ◽  
pp. 264-266 ◽  
Author(s):  
S. Tisserant ◽  
Tran N. Truong
Keyword(s):  
Quark Mass ◽  
Light Quark ◽  
Mass Difference ◽  
Light Quark Mass

RECENT PROGRESS ON D SEMILEPTONIC DECAYS FROM LATTICE QCD

2011 ◽  
Vol 02 ◽  
pp. 83-87
Author(s):  
HEECHANG NA
Keyword(s):  
Lattice Qcd ◽  
Recent Progress ◽  
State Of The Art ◽  
Semileptonic Decays ◽  
Experimental Measurements ◽  
Lattice Calculations

This is a brief review of recent lattice calculations of D semileptonic decays. This presentation includes only calculations that do not use the quenched approximation. A new state-of-the-art calculation from the HPQCD collaboration is discussed and compared with other calculations and experimental measurements.

scholarly journals Chiral Perturbation Theory for Three-Flavour Lattice QCD with Isospin Splitting

2016 ◽  
Vol 2016 ◽  
pp. 1-6
Author(s):  
S. Engelnkemper ◽  
G. Münster
Keyword(s):  
Perturbation Theory ◽  
Lattice Qcd ◽  
Chiral Perturbation Theory ◽  
Lattice Spacing ◽  
Light Quark ◽  
Mass Difference ◽  
Finite Lattice ◽  
Chiral Perturbation ◽  
Isospin Splitting ◽  
The Masses

An important tool for the analysis of results of numerical simulations of lattice QCD is chiral perturbation theory. In the Wilson chiral perturbation theory the effects of the finite lattice spacingaare taken into account. In recent years the effects of isospin splitting on the masses of hadrons have been investigated in the Monte Carlo simulations. Correspondingly, in this paper we derive the expansions of the masses of the pseudoscalar mesons in chiral perturbation theory at next-to-leading order for twisted mass lattice QCD with three light quark flavours, taking the mass difference between the up- and downquarks into account. The results include terms up to ordersmq2in the quark masses,Δm2in the mass splitting between up- and downquarks, anda2in the lattice spacing, respectively.

scholarly journals LATTICE QCD CALCULATION OF NUCLEAR FORCES

2008 ◽  
Vol 23 (27n30) ◽  
pp. 2281-2284 ◽  
Author(s):  
NORIYOSHI ISHII ◽  
SINYA AOKI ◽  
TETSUO HATSUDA
Keyword(s):  
Lattice Qcd ◽  
Light Quark ◽  
Tensor Force ◽  
Type Equation ◽  
Mass Region ◽  
Wave Functions ◽  
Central Force ◽  
Repulsive Core ◽  
Nuclear Forces ◽  
Light Quark Mass

Quenched lattice QCD results of nuclear forces are presented. Inter-nucleon potentials are constructed from Bethe-Salpeter wave functions of two nucleon states by using a Schrödinger-type equation. The results of the central force in 1S0 channel posses the repulsive core at short distance as well as the attraction at medium distance, both of which are enhanced in the light quark mass region. A preliminary result on the tensor force is also presented with the central force in 3S1 channel.

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.

scholarly journals Bs → Kℓv form factors with 2+1 flavors

2018 ◽  
Vol 175 ◽  
pp. 13008 ◽  
Author(s):  
Yuzhi Liu ◽  
Jon A. Bailey ◽  
A. Bazavov ◽  
C. Bernard ◽  
C. M. Bouchard ◽  
...  
Keyword(s):  
Quark Mass ◽  
Strange Quark ◽  
Lattice Spacing ◽  
Light Quark ◽  
Form Factors ◽  
Ckm Matrix ◽  
Strange Quark Mass ◽  
Light Quark Mass ◽  
B Quark

Using the MILC 2+1 flavor asqtad quark action ensembles, we are calculating the form factors f0 and f+ for the semileptonic Bs → Kℓv decay. A total of six ensembles with lattice spacing from ≈ 0.12 to 0.06 fm are being used. At the coarsest and finest lattice spacings, the light quark mass m’l is one-tenth the strange quark mass m’s. At the intermediate lattice spacing, the ratio m’l/m’s ranges from 0.05 to 0.2. The valence b quark is treated using the Sheikholeslami-Wohlert Wilson-clover action with the Fermilab interpretation. The other valence quarks use the asqtad action. When combined with (future) measurements from the LHCb and Belle II experiments, these calculations will provide an alternate determination of the CKM matrix element |Vub|.

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