scholarly journals QCD NLO fragmentation functions for c or b¯ quark to Bc or Bc* meson and their application

2019 ◽  
Vol 100 (3) ◽  
Author(s):  
Xu-Chang Zheng ◽  
Chao-Hsi Chang ◽  
Tai-Fu Feng ◽  
Xing-Gang Wu
Keyword(s):  
Bc Meson ◽  
Fragmentation Functions ◽  
B Quark

scholarly journals Contribution of the Darwin operator to non-leptonic decays of heavy quarks

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Alexander Lenz ◽  
Maria Laura Piscopo ◽  
Aleksey V. Rusov
Keyword(s):  
Standard Technique ◽  
Quark Propagator ◽  
Leptonic Decay ◽  
Leptonic Decays ◽  
Interference Contribution ◽  
The Standard Model ◽  
Strength Tensor ◽  
Quark Flavour ◽  
Quark Decay ◽  
B Quark

Abstract We compute the Darwin operator contribution ($$ 1/{m}_b^3 $$ 1 / m b 3 correction) to the width of the inclusive non-leptonic decay of a B meson (B+, Bd or Bs), stemming from the quark flavour-changing transition b → $$ {q}_1{\overline{q}}_2{q}_3 $$ q 1 q ¯ 2 q 3 , where q1, q2 = u, c and q3 = d, s. The key ideas of the computation are the local expansion of the quark propagator in the external gluon field including terms with a covariant derivative of the gluon field strength tensor and the standard technique of the Heavy Quark Expansion (HQE). We confirm the previously known expressions of the $$ 1/{m}_b^3 $$ 1 / m b 3 contributions to the semi-leptonic decay b → $$ {q}_1\mathrm{\ell}{\overline{\nu}}_{\mathrm{\ell}} $$ q 1 ℓ ν ¯ ℓ , with ℓ = e, μ, τ and of the $$ 1/{m}_b^2 $$ 1 / m b 2 contributions to the non-leptonic modes. We find that this new term can give a sizeable correction of about −4 % to the non-leptonic decay width of a B meson. For Bd and Bs mesons this turns out to be the dominant correction to the free b-quark decay, while for the B+ meson the Darwin term gives the second most important correction — roughly 1/2 to 1/3 of the phase space enhanced Pauli interference contribution. Due to the tiny experimental uncertainties in lifetime measurements the incorporation of the Darwin term contribution is crucial for precision tests of the Standard Model.

scholarly journals Probing quark fragmentation functions for baryon production in unpolarized e+e− annihilation

1995 ◽  
Vol 445 (2-3) ◽  
pp. 380-396 ◽  
Author(s):  
Kun Chen ◽  
Gary R. Goldstein ◽  
R.L. Jaffe ◽  
Xiangdong Ji
Keyword(s):  
Baryon Production ◽  
Quark Fragmentation ◽  
Fragmentation Functions

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|.

scholarly journals Search for the Bc meson

1997 ◽  
Vol 398 (1-2) ◽  
pp. 207-222 ◽  
Author(s):  
P. Abreu ◽  
W. Adam ◽  
T. Adye ◽  
I. Ajinenko ◽  
G.D. Alekseev ◽  
...  
Keyword(s):  
Bc Meson

One-particle fragmentation functions in the massless Schwinger model

1994 ◽  
Vol 326 (1-2) ◽  
pp. 154-160 ◽  
Author(s):  
Jun Liu ◽  
Cheuk-Yin Wong ◽  
Chia C. Shih ◽  
Ren Chuan Wang
Keyword(s):  
Schwinger Model ◽  
Particle Fragmentation ◽  
Fragmentation Functions

BESSEL-WEIGHTED ASYMMETRIES AND TRANSVERSE SPIN EFFECTS

2012 ◽  
Vol 20 ◽  
pp. 168-176
Author(s):  
LEONARD GAMBERG
Keyword(s):  
Transverse Momentum ◽  
Cross Section ◽  
Parton Distribution ◽  
Evolution Equations ◽  
Distribution Functions ◽  
Transverse Spin ◽  
High Transverse Momentum ◽  
Transverse Momentum Dependent ◽  
Fragmentation Functions ◽  
The Cross

We consider the cross section for semi-inclusive deep inelastic scattering in Fourier space, conjugate to the outgoing hadron's transverse momentum, where convolutions of transverse momentum dependent parton distribution functions and fragmentation functions become simple products. Individual asymmetric terms in the cross section can be projected out by means of a generalized set of weights involving Bessel functions. Advantages of employing these Bessel weights are that they suppress (divergent) contributions from high transverse momentum and that soft factors cancel in (Bessel-) weighted asymmetries. Also, the resulting compact expressions immediately connect to previous work on evolution equations for transverse momentum dependent parton distribution and fragmentation functions and to quantities accessible in lattice QCD. Bessel-weighted asymmetries are thus model independent observables that augment the description and our understanding of correlations of spin and momentum in nucleon structure.

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