scholarly journals Ratios of heavy hadron semileptonic decay rates

2011 ◽  
Vol 83 (3) ◽  
Author(s):  
Michael Gronau ◽  
Jonathan L. Rosner
Keyword(s):  
Semileptonic Decay ◽  
Decay Rates ◽  
Heavy Hadron

scholarly journals Radiative Corrections to Semileptonic Decay Rates

2019 ◽  
Author(s):  
Christopher Sachrajda ◽  
Matteo Di Carlo ◽  
Guido Martinelli ◽  
Davide Giusti ◽  
Vittorio Lubicz ◽  
...  
Keyword(s):  
Semileptonic Decay ◽  
Decay Rates ◽  
Radiative Corrections

scholarly journals Relations between b → cτν decay modes in scalar models

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
Stefan Schacht ◽  
Amarjit Soni
Keyword(s):  
Decay Mode ◽  
Semileptonic Decay ◽  
New Physics ◽  
Decay Rates ◽  
Scalar Form Factor ◽  
Scalar Form ◽  
Decay Modes ◽  
Pseudoscalar Mesons ◽  
Quark Level ◽  
Level Transition

Abstract As a consequence of the Ward identity for hadronic matrix elements, we find relations between the differential decay rates of semileptonic decay modes with the underlying quark-level transition b → cτν, which are valid in scalar models. The decay-mode dependent scalar form factor is the only necessary theoretical ingredient for the relations. Otherwise, they combine measurable decay rates as a function of the invariant mass-squared of the lepton pair q2 in such a way that a universal decay-mode independent function is found for decays to vector and pseudoscalar mesons, respectively. This can be applied to the decays $$ B\to {D}^{\ast}\tau v,{B}_s\to {D}_s^{\ast}\tau v,{B}_c\to J/\psi \tau v $$ B → D ∗ τv , B s → D s ∗ τv , B c → J / ψτv and B → Dτv, Bs → Dsτv, Bc → ηcτv, with implications for R(D(*)), $$ R\left({D}_s^{\left(\ast \right)}\right) $$ R D s ∗ , R(J/ψ), R(ηc), and ℬ(Bc → τv). The slope and curvature of the characteristic q2-dependence is proportional to scalar new physics parameters, facilitating their straight forward extraction, complementary to global fits.

scholarly journals The Kalman-Tran-D'Souza model and the semileptonic decay rates of heavy baryons

2001 ◽  
Vol 93 (1-3) ◽  
pp. 3-8 ◽  
Author(s):  
I. D'Souza ◽  
C.S. Kalman ◽  
P.Yu. Kulikov ◽  
I.M. Narodetskii
Keyword(s):  
Semileptonic Decay ◽  
Decay Rates ◽  
Heavy Baryons

scholarly journals Relativistic calculations of R(D(∗)), R(Ds(∗)), R(ηc) and R(J/ψ)

2020 ◽  
Vol 35 (17) ◽  
pp. 2050076
Author(s):  
Tian Zhou ◽  
Tianhong Wang ◽  
Yue Jiang ◽  
Xiao-Ze Tan ◽  
Geng Li ◽  
...  
Keyword(s):  
Experimental Data ◽  
Standard Model ◽  
Semileptonic Decay ◽  
Form Factors ◽  
Relativistic Correction ◽  
New Physics ◽  
Decay Rates ◽  
The Standard Model ◽  
Model Predictions

Recently, the deviation of the ratios [Formula: see text], [Formula: see text] and [Formula: see text] have been found between experimental data and the Standard Model predictions, which may be the hint of new physics. In this work, we calculate these ratios within the Standard Model by using the improved instantaneous Bethe–Salpeter method. The emphasis is pad to the relativistic correction of the form factors. The results are [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text], which are consistent with predictions of other models and the experimental data. The semileptonic decay rates and corresponding form factors at zero recoil are also given.

scholarly journals WEAK MATRIX ELEMENTS AND |Vcb| IN HQEFT

2000 ◽  
Vol 15 (12) ◽  
pp. 1817-1857 ◽  
Author(s):  
W. Y. WANG ◽  
Y. L. WU ◽  
Y. A. YAN
Keyword(s):  
Heavy Quark ◽  
Axial Vector ◽  
Form Factors ◽  
Effective Field ◽  
Decay Rates ◽  
Effective Theory ◽  
Matrix Elements ◽  
Normalization Condition ◽  
Heavy Hadron ◽  
New Formulation

The heavy quark effective field theory (HQEFT) containing both effective "quark fields" and "antiquark fields" is investigated in detail. By integrating out (but not neglecting) the effective antiquark fields, we present a new formulation of effective theory which differs from the usual heavy quark effective theory (HQET) and exhibits valuable features because of the inclusion of the contributions from the antiquark fields. Matrix elements of vector and axial vector heavy quark currents between pseudoscalar and vector mesons containing a heavy quark (b or c) are then evaluated systematically up to the order of [Formula: see text] and parametrized by a set of universal form factors. With a consistent normalization condition between the effective heavy hadron states, the form factors at zero recoil are related to the ground state meson masses, which enables us to estimate the values of form factors at zero recoil. In particular, Luke's theorem comes out automatically in the new formulation of HQEFT without the need of imposing the equation of motion [Formula: see text]. Consequently, the differential decay rates of both B → D*lν and B→Dlν do not receive 1/mQ order corrections at zero recoil, which is not the case in the usual HQET. Thus we quote that the Cabibbo–Kobayashi–Maskawa matrix element |Vcb| can nicely be extracted from either of these two exclusive semileptonic decays at the order of [Formula: see text]. Our estimates for |Vcb| are presented.

scholarly journals SEMILEPTONIC DECAY OF Bc MESON INTO $c\bar c$ STATES IN A QCD POTENTIAL MODEL

2013 ◽  
Vol 28 (19) ◽  
pp. 1350097 ◽  
Author(s):  
KRISHNA KINGKAR PATHAK ◽  
D. K. CHOUDHURY
Keyword(s):  
Potential Model ◽  
Semileptonic Decay ◽  
Form Factors ◽  
Spin Symmetry ◽  
Decay Rates ◽  
Effective Theory ◽  
Recoil Momentum ◽  
Cornell Potential ◽  
Bc Meson ◽  
Kinematic Point

The slope and curvature of Isgur–Wise function for Bc meson is computed in a QCD potential model in two different approaches of choosing the perturbative term of the Cornell potential. Based on heavy quark effective theory the exclusive semileptonic decay rates of Bc meson into the [Formula: see text] states are exploited. Spin symmetry breaking effects are ignored up to a particular point and the form factors are connected with Isgur–Wise function for other kinematic point since the recoil momentum of [Formula: see text] from Bc is small due to its heavy mass.

Recent Results of D Physics on BESII

2006 ◽  
Vol 21 (27) ◽  
pp. 5430-5435
Author(s):  
◽  
Hai Long Ma
Keyword(s):  
D Mesons ◽  
Semileptonic Decay ◽  
Branching Fractions ◽  
Semileptonic Decays ◽  
Decay Rates ◽  
Inclusive Decays ◽  
The Absolute

Based on the data sample of 33 pb-1 collected at and around 3.773 GeV with the BESII detector at the BEPC collider, the absolute branching fractions for some exclusive semileptonic decays and inclusive decays of D mesons have been measured. With the measured branching fractions, the ratio of the two partial widths of the decays D0 → K-μ+νμ and [Formula: see text] is determined to be 0.87 ± 0.24 ± 0.15, which supports that the isospin conversation holds in the exclusive semimuonic decays of D0 and D- mesons. The ratio of the vector to pseudoscalar semileptonic decay rates [Formula: see text] is determined to be 0.57 ± 0.17 ± 0.02.

AN EFFECTIVE LAGRANGIAN CALCULATION OF THE SEMILEPTONIC DECAY MODES OF THE τ LEPTON

1990 ◽  
Vol 05 (14) ◽  
pp. 2737-2753 ◽  
Author(s):  
ERIC BRAATEN ◽  
ROBERT J. OAKES ◽  
SZE-MAN TSE
Keyword(s):  
Vector Meson ◽  
Ad Hoc ◽  
Semileptonic Decay ◽  
Branching Fractions ◽  
Decay Rates ◽  
Coupling Constants ◽  
Vector Meson Dominance ◽  
Decay Modes ◽  
Effective Lagrangian ◽  
Pseudoscalar Mesons

The semileptonic decay rates of the τ lepton into final states containing up to three pseudoscalar mesons are calculated using a general low energy effective Lagrangian for pseudoscalar and vector mesons with U (3)× U (3) chiral symmetry. Symmetry breaking is taken into account in the meson masses and mixing angles. All of the coupling constants in the Lagrangian are determined empirically from vector meson decay data without additional ad hoc hypotheses such as vector meson dominance. The results compare well with the measured decay rates where data are available. No unexpectedly large branching fractions are found that might account for the “missing” decay modes of the τ.

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