scholarly journals Search forD0−D¯0mixing using semileptonic decay modes

2004 ◽  
Vol 70 (9) ◽  
Author(s):  
B. Aubert ◽  
R. Barate ◽  
D. Boutigny ◽  
F. Couderc ◽  
J.-M. Gaillard ◽  
...  
Keyword(s):  
Semileptonic Decay ◽  
Decay Modes

scholarly journals Search forD0−D¯0mixing using doubly flavor tagged semileptonic decay modes

2007 ◽  
Vol 76 (1) ◽  
Author(s):  
B. Aubert ◽  
M. Bona ◽  
D. Boutigny ◽  
Y. Karyotakis ◽  
J. P. Lees ◽  
...  
Keyword(s):  
Semileptonic Decay ◽  
Decay Modes

scholarly journals Bd MIXING AND PROSPECTS FOR Bs MIXING AT DØ

2005 ◽  
Vol 20 (15) ◽  
pp. 3513-3517
Author(s):  
◽  
Tulika Bose
Keyword(s):  
Oscillation Frequency ◽  
Semileptonic Decay ◽  
Large Set ◽  
Matrix Elements ◽  
Ckm Matrix ◽  
Decay Modes ◽  
Ckm Matrix Elements ◽  
Powerful Constraint ◽  
Flavor Tagging

Measurement of the Bs oscillation frequency via Bs mixing analyses provides a powerful constraint on the CKM matrix elements. The study of Bd oscillations is an important step towards Bs mixing and preliminary measurements of Δmd have been made with ~250 pb-1 of data collected with the upgraded Run II DØ detector. Different flavor tagging algorithms have been developed and are being optimized for use on a large set of Bs mesons that have been reconstructed in different semileptonic decay modes.

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.

SEARCH FOR $D^0-\overline{D}^0$ MIXING USING SEMILEPTONIC DECAYS

2005 ◽  
Vol 20 (16) ◽  
pp. 3686-3688 ◽  
Author(s):  
◽  
Kevin T. Flood
Keyword(s):  
Neural Networks ◽  
Time Dependence ◽  
Decay Time ◽  
Semileptonic Decay ◽  
Mass Difference ◽  
Semileptonic Decays ◽  
Decay Modes ◽  
Upper Limit ◽  
Flavor Tagging ◽  
Babar Detector

Based on an 87-fb-1 dataset collected by the Babar detector at the PEP-II asymmetric-energy B-Factory, a search for [Formula: see text] mixing has been made using the semileptonic decay modes D*+ → π+D0, D0 → Kev (+c.c.) . The use of these modes allows unambiguous flavor tagging and a combined fit of the D0 decay time and D*+-D0 mass difference (ΔM) distributions. The high-statistics sample of unmixed semileptonic D0 decays is used to model the ΔM distribution and time-dependence of mixed events directly from the data. Neural networks are used to select events and reconstruct the D0. A result consistent with no charm mixing has been obtained, R mix = 0.0023 ± 0.0012 ± 0.0004. This corresponds to an upper limit of R mix < 0.0042 (90% CL).

scholarly journals Search forD0D¯0Mixing in Semileptonic Decay Modes

1996 ◽  
Vol 77 (12) ◽  
pp. 2384-2387 ◽  
Author(s):  
E. M. Aitala ◽  
S. Amato ◽  
J. C. Anjos ◽  
J. A. Appel ◽  
D. Ashery ◽  
...  
Keyword(s):  
Semileptonic Decay ◽  
Decay Modes

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.

scholarly journals The role of right-handed neutrinos in b → cτ (πντ, ρντ, μ$$ \overline{\nu} $$μντ)$$ \overline{\nu} $$τ from visible final-state kinematics

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
Neus Penalva ◽  
Eliecer Hernández ◽  
Juan Nieves
Keyword(s):  
Semileptonic Decay ◽  
Massive Particle ◽  
New Physics ◽  
Experimental Information ◽  
Final State ◽  
Spin Asymmetries ◽  
Decay Modes ◽  
Lepton Flavor ◽  
Rule Out

Abstract In the context of lepton flavor universality violation (LFUV) studies, we fully derive a general tensor formalism to investigate the role that left- and right-handed neutrino new-physics (NP) terms may have in b → cτ$$ \overline{\nu} $$ ν ¯ τ transitions. We present, for several extensions of the Standard Model (SM), numerical results for the Λb → Λcτ$$ \overline{\nu} $$ ν ¯ τ semileptonic decay, which is expected to be measured with precision at the LHCb. This reaction can be a new source of experimental information that can help to confirm, or maybe rule out, LFUV presently seen in $$ \overline{B} $$ B ¯ meson decays. The present study analyzes observables that can help in distinguishing between different NP scenarios that otherwise provide very similar results for the branching ratios, which are our currently best hints for LFUV. Since the τ lepton is very short-lived, we consider three subsequent τ-decay modes, two hadronic πντ and ρντ and one leptonic μ$$ \overline{\nu} $$ ν ¯ μντ, which have been previously studied for $$ \overline{B} $$ B ¯ → D(*) decays. Within the tensor formalism that we have developed in previous works, we re-obtain the expressions for the differential decay width written in terms of visible (experimentally accessible) variables of the massive particle created in the τ decay. There are seven different τ angular and spin asymmetries that are defined in this way and that can be extracted from experiment. Those asymmetries provide observables that can help in constraining possible SM extensions.

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