scholarly journals B-meson decays into final states with a τ lepton

2014 ◽  
Vol 29 (07) ◽  
pp. 1430007 ◽  
Author(s):  
Abner Soffer
Keyword(s):  
B Mesons ◽  
B Meson ◽  
Branching Fraction ◽  
Large Data ◽  
New Physics ◽  
Final States ◽  
Initial State ◽  
Lepton Flavor ◽  
Event Reconstruction ◽  
The Standard Model

Decays of B mesons into final states containing a τ lepton are sensitive to new charged current interactions that break lepton-flavor universality. These decays have been studied only at e+e- colliders, where the low-background environment and well-known initial state make it possible to observe small signals with undetectable neutrinos. In particular, the large data samples of the B factories and recent advances in techniques for full-event reconstruction have led to evidence for the decay B+→τ+ ντ and unambiguous observation of the decays [Formula: see text]. These results exclude large regions of the parameter space for a variety of new physics models. Furthermore, the branching fraction for [Formula: see text] has been measured to be higher than the Standard Model expectation by more than three standard deviations, making this an interesting topic for further research. This paper reviews the theoretical and experimental status of this topic, summarizing the results at this time and outlining the path for further improvements.

scholarly journals Probing new physics in semileptonic $$\Xi _{b}\rightarrow \Lambda (\Xi _{c})\tau ^{-}\bar{\nu }_{\tau }$$ decays

2019 ◽  
Vol 79 (10) ◽  
Author(s):  
Jiao Zhang ◽  
Xiuyun An ◽  
Ruirui Sun ◽  
Jianfeng Su
Keyword(s):  
Standard Model ◽  
B Meson ◽  
Branching Fraction ◽  
Branching Fractions ◽  
New Physics ◽  
Effective Theory ◽  
Tau Decays ◽  
Lepton Flavor ◽  
Measurement Results ◽  
Quark Level

Abstract Recently, several observed anomalies in semileptonic B meson decays have implied hints of lepton flavor universal violation. Motivated by these inspiring results, we study the baryon decays $$\Xi _{b}\rightarrow \Lambda (\Xi _{c})\tau ^{-}\bar{\nu }_{\tau }$$Ξb→Λ(Ξc)τ-ν¯τ which are mediated by $$b\rightarrow u(c)\tau ^{-}\bar{\nu }_{\tau }$$b→u(c)τ-ν¯τ transitions at quark level in the Standard Model and different New Physics scenarios. In the framework of the extended Standard Model on assuming a general effective theory, we constrain the Wilson coefficients of the NP operators using the experimental measurement results for the $$Br(B_{c}^+\rightarrow \tau ^+ \nu _{\tau })$$Br(Bc+→τ+ντ), $$R^{l}_{\pi }$$Rπl, $$R_{D^{(*)}}$$RD(∗), $$R_{J/\psi }$$RJ/ψ and $$F_{L}^{D^{*}}$$FLD∗ anomalies and investigate their New Physics effects on several observables relative to the $$\Xi _{b}\rightarrow \Lambda (\Xi _{c})\tau ^{-}\bar{\nu }_{\tau }$$Ξb→Λ(Ξc)τ-ν¯τ decays. We mention the differential branching fraction $${\text {d}}Br/{\text {d}}q^2$$dBr/dq2, the ratio of branching fractions $$R(q^2)$$R(q2), the lepton-side forward–backward asymmetry $$A_{FB}(q^2)$$AFB(q2), the longitudinal polarization $$P_{L}^{\Lambda (\Xi _{c})}(q^2)$$PLΛ(Ξc)(q2) of the daughter baryons $$\Lambda (\Xi _{c})$$Λ(Ξc) and $$P_{L}^{\tau }(q^2)$$PLτ(q2) of the $$\tau $$τ lepton, and the convexity parameter $$C_{F}(q^2)$$CF(q2).

scholarly journals SIGNATURES OF NEW PHYSICS IN DILEPTONIC B-DECAYS

2006 ◽  
Vol 21 (12) ◽  
pp. 2617-2634 ◽  
Author(s):  
S. RAI CHOUDHURY ◽  
A. S. CORNELL ◽  
NAVEEN GAUR ◽  
G. C. JOSHI
Keyword(s):  
B Mesons ◽  
B Meson ◽  
Higgs Doublet ◽  
New Physics ◽  
Final State ◽  
Decay Modes ◽  
Leptonic Decays ◽  
The Standard Model ◽  
Doublet Model ◽  
Two Higgs Doublet Model

Leptonic decays of B-mesons are theoretically very clean probes for testing the Standard Model (SM) and possible physics beyond it. Amongst the various leptonic decays of the B-meson, the pure dileptonic decay B → ℓ+ ℓ- is very important, as this mode is helicity suppressed in the SM but can be substantially enhanced in some of the models beyond the SM, such as supersymmetric (SUSY) theories and the two Higgs doublet model (2HDM). Although the purely dileptonic decay mode is helicity suppressed in the SM its associated mode B → ℓ+ ℓ-γ does not have the same suppression, due to the presence of γ in the final state. In this paper we will also analyze the effects of enhanced Z-penguins on these two decay modes.

RARE HADRONIC B DECAYS

2004 ◽  
Vol 19 (06) ◽  
pp. 918-933 ◽  
Author(s):  
J. R. FRY
Keyword(s):  
Standard Model ◽  
Rare Decays ◽  
B Mesons ◽  
Theoretical Calculations ◽  
New Physics ◽  
Final States ◽  
B Decays ◽  
Theoretical Approaches ◽  
The Standard Model ◽  
Hadronic Final States

Recent data from the rare decays of B mesons into hadronic final states is presented from BaBar, Belle, CDF and CLEO. Where possible the data are compared with theoretical calculations, with the twin aims of further testing the Standard Model and searching for evidence of new physics. A brief description is given of some theoretical approaches in order to indicate which decays are the most sensitive for further study.

SEARCH FOR NEW PHYSICS IN eμX DATA AT THE TEVATRON USING SLEUTH: A QUASI-MODEL-INDEPENDENT SEARCH STRATEGY FOR NEW PHYSICS

2001 ◽  
Vol 16 (supp01b) ◽  
pp. 888-890
Author(s):  
◽  
BRUCE KNUTESON
Keyword(s):  
Standard Model ◽  
Search Strategy ◽  
New Physics ◽  
Beyond The Standard Model ◽  
Final States ◽  
Final State ◽  
The Standard Model ◽  
Model Independent

We present a quasi-model-independent search for physics beyond the standard model. We define final states to be studied, and construct a rule that identifies a set of variables appropriate for any particular final state. A new algorithm ("Sleuth") searches for regions of excess in the space of those variables and quantifies the significance of any detected excess. After demonstrating the sensititvity of the method, we apply it to the semi-inclusive channel eμX collected in ≈108 pb -1 of [Formula: see text] collisions at [Formula: see text] at the DØ experiment at the Fermilab Tevatron. We find no evidence of new high pT physics in this sample.

scholarly journals One Loop Corrections to Decay \(\tau\rightarrow \mu\gamma\) in Economical 3-3-1 Model

2015 ◽  
Vol 25 (2) ◽  
pp. 113
Author(s):  
Truong Trong Thuc ◽  
Le Tho Hue ◽  
Dinh Phan Khoi ◽  
Nguyen Thanh Phong
Keyword(s):  
Standard Model ◽  
New Physics ◽  
Beyond The Standard Model ◽  
Lepton Flavor ◽  
Unitary Gauge ◽  
The Standard Model ◽  
Charged Leptons

Lepton flavor violating (cLFV) decays of charged leptons such as \(\tau\rightarrow \mu\gamma\), \(\tau\rightarrow e\gamma\), \(\mu\rightarrow e\gamma\),..., are now the subjects of experiments as signals of new Physics beyond the Standard Model (SM). In the limit of the unitary gauge, we prove that contributions from one loop corrections to the above decays are very small in the framework of the economical 3-3-1 model.

Study of the semileptonic Bc → ηcτ−v̄τ decay in W′ model

2021 ◽  
Author(s):  
S. Mahata ◽  
P. Maji ◽  
S. Biswas ◽  
S. Sahoo
Keyword(s):  
Standard Model ◽  
Branching Ratio ◽  
New Physics ◽  
Experimental Results ◽  
Lepton Flavor ◽  
The Standard Model ◽  
Text Model

Recently, many discrepancies between the Standard Model (SM) predictions and experimental results have been found in [Formula: see text] quark transitions. Motivated by these discrepancies, we investigated the semileptonic [Formula: see text] decay in [Formula: see text] model. In this paper, we have estimated different decay observables such as branching ratio, lepton flavor universality (LFU) ratio [Formula: see text] and forward–backward asymmetry in the SM as well as in the [Formula: see text] model. In [Formula: see text] model, we find significant deviations from the SM for the observables except for the forward–backward asymmetry. This deviation gives us a possible indication of new physics (NP).

B-Meson Decay

2017 ◽  
Vol 3 (3) ◽  
Author(s):  
Joaquim Matias
Keyword(s):  
Large Hadron Collider ◽  
Rare Decays ◽  
B Mesons ◽  
B Meson ◽  
Hadron Collider ◽  
New Physics ◽  
Meson Decay ◽  
B Meson Decay ◽  
Particle Physicist

Particle physicist Joaquim Matias analyzes recent results from the Large Hadron Collider—in particular, rare decays of B-mesons that suggest the violation of leptonic universality—for evidence of New Physics.

scholarly journals η′K PUZZLE OF B MESON DECAYS AND NEW PHYSICS EFFECTS IN THE TC2 MODEL

2001 ◽  
Vol 16 (07) ◽  
pp. 441-455 ◽  
Author(s):  
ZHENJUN XIAO ◽  
WENJUN LI ◽  
GONGRU LU ◽  
LIBO GUO
Keyword(s):  
Standard Model ◽  
B Meson ◽  
New Physics ◽  
Decay Rates ◽  
Low Energy ◽  
Effective Hamiltonian ◽  
B Meson Decays ◽  
The Standard Model ◽  
Model Predictions ◽  
Input Parameters

Using the low energy effective Hamiltonian with the generalized factorization, we calculate the new physics contributions to B→π+π-, Kπ and Kη′ in the topcolor-assisted-technicolor (TC2) model, and compare the results with the available data. By using [Formula: see text] preferred by the CLEO data of B→π+π-decay, we find that the new physics enhancements to B→ Kη′ decays are significant in size, ~ 50% with respect to the standard model predictions, insensitive to the variations of input parameters and hence provide a simple and plausible new physics interpretation for the observed unexpectedly large B→ Kη′ decay rates.

Sign in / Sign up

Export Citation Format

Share Document