scholarly journals Study of electroweak penguin B decays at Belle II experiment

2021 ◽  
Vol 2145 (1) ◽  
pp. 012018
Author(s):  
J Ineead ◽  
S Nishida ◽  
B Asavapibhop ◽  
N Suwonjandee
Keyword(s):  
Branching Fraction ◽  
Neutral Current ◽  
New Physics ◽  
Lepton Flavor ◽  
Flavor Changing ◽  
Penguin Diagram ◽  
The Status ◽  
Flavor Changing Neutral Current ◽  
Belle Ii ◽  
Exclusive Decay

Abstract The electroweak b → sll (l = e, µ) transition is a flavor-changing neutral current process that mediates through a one-loop penguin diagram. The decay is considered to be a good probe for the New Physics as particles predicted in the beyond Standard Model theories can enter into the loop. The exclusive decay B → K (*) l + l − was first observed by the Belle experiment and it provides many observables such as the branching fraction, CP asymmetry, forward-backward asymmetry, and other angular observables. Recently, the LHCb experiment has reported some clue of a lepton flavor universality violation from the branching fraction ratio of the B → Kµ + µ − and B → Ke + e − decays. In this presentation, we report the status of the B → Kl + l − decay analysis at the Belle II experiment which started the data taking in 2019. We also, present an activity at the Belle II Chulalongkorn University group where we study the B → KJ/ψ decay which has the same topology as the B → Kl + l − .

scholarly journals Top and beauty synergies in SMEFT-fits at present and future colliders

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Stefan Bißmann ◽  
Cornelius Grunwald ◽  
Gudrun Hiller ◽  
Kevin Kröninger
Keyword(s):  
Effective Field Theory ◽  
Top Quark ◽  
Neutral Current ◽  
New Physics ◽  
Effective Field ◽  
Flavor Changing ◽  
Flavor Changing Neutral Current ◽  
Three Stages ◽  
Belle Ii ◽  
Existing Data

Abstract We perform global fits within Standard Model Effective Field Theory (SMEFT) combining top-quark pair production processes and decay with b → s flavor changing neutral current transitions and Z → $$ b\overline{b} $$ b b ¯ in three stages: using existing data from the LHC and B-factories, using projections for the HL-LHC and Belle II, and studying the additional new physics impact from a future lepton collider. The latter is ideally suited to directly probe ℓ+ℓ− → $$ t\overline{t} $$ t t ¯ transitions. We observe powerful synergies in combining both top and beauty observables as flat directions are removed and more operators can be probed. We find that a future lepton collider significantly enhances this interplay and qualitatively improves global SMEFT fits.

scholarly journals Status of rare exclusive B meson decays in 2018

2018 ◽  
Vol 33 (18n19) ◽  
pp. 1830016 ◽  
Author(s):  
Johannes Albrecht ◽  
Stefanie Reichert ◽  
Danny van Dyk
Keyword(s):  
B Meson ◽  
Experimental Situation ◽  
Neutral Current ◽  
New Physics ◽  
Beyond The Standard Model ◽  
Lepton Flavor ◽  
Flavor Changing ◽  
Theoretical Status ◽  
Flavor Changing Neutral Current ◽  
B Quark

This review discusses the present experimental and theoretical status of rare flavor-changing neutral current b-quark decays at the beginning of 2018. It includes a discussion of the experimental situation and details of the currently observed anomalies in measurements of flavor observables, including lepton flavor universality. Progress on the theory side within and beyond the Standard Model theory is also discussed, together with potential New Physics interpretations of the present measurements.

Lepton flavor violating decays in model

2019 ◽  
Vol 97 (12) ◽  
pp. 1270-1276
Author(s):  
P. Nayek ◽  
P. Maji ◽  
S. Sahoo
Keyword(s):  
Standard Model ◽  
Neutral Current ◽  
Branching Ratios ◽  
New Physics ◽  
Beyond The Standard Model ◽  
Lepton Flavor ◽  
Flavor Changing ◽  
The Standard Model ◽  
Flavor Changing Neutral Current ◽  
Text Model

Motivated by the hints of lepton flavor violating (LFV) decays, we study Bd,s → μτ, Bs,d → τe, and τ– → e– + e+ + e– decays in [Formula: see text] model. These LFV decays present interesting patterns that may reveal the shape of new physics beyond the standard model. Considering the effect of both Z- and [Formula: see text]-mediated flavor-changing neutral current we calculate the branching ratios for these decays. We find the branching ratios [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text].

scholarly journals Structure of flavor changing Goldstone boson interactions

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Jin Sun ◽  
Yu Cheng ◽  
Xiao-Gang He
Keyword(s):  
Symmetry Breaking ◽  
Model Building ◽  
Neutral Current ◽  
Goldstone Boson ◽  
New Physics ◽  
Majorana Neutrino ◽  
Neutrino Masses ◽  
Type I ◽  
Flavor Changing ◽  
Flavor Changing Neutral Current

Abstract General flavor changing Goldstone boson (GB) interactions with fermions from a spontaneous global U(1)G symmetry breaking are discussed. This GB may be the Axion, solving the strong QCD CP problem, if there is a QCD anomaly for the assignments of quarks U(1)G charge. Or it may be the Majoron, producing seesaw Majorana neutrino masses by lepton number violation, if the symmetry breaking scale is much higher than the electroweak scale. It may also, in principle, play the roles of Axion and Majoron simultaneously as far as providing solution for the strong CP problem and generating a small Majorana neutrino masses are concerned. Great attentions have been focused on flavor conserving GB interactions. Recently flavor changing Axion and Majoron models have been studied in the hope to find new physics from rare decays in the intensity frontier. In this work, we will provide a systematic model building aspect study for flavor changing neutral current (FCNC) GB interactions in the fermion sectors, or separately in the quark, charged lepton and neutrino sectors and will identify in detail the sources of FCNC interactions in a class of beyond standard model with a spontaneous global U(1)G symmetry breaking. We also provide a general proof of the equivalence of using physical GB components and GB broken generators for calculating GB couplings to two gluons and two photons, and discuss some issues related to spontaneous CP violation models. Besides, we will also provide some details for obtaining FCNC GB interactions in several popular models, such as the Type-I, -II, -III seesaw and Left-Right symmetric models, and point out some special features in these models.

scholarly journals PREDICTIONS FOR $B \to \tau \bar{\mu} + \mu \bar{\tau}$

2013 ◽  
Vol 28 (31) ◽  
pp. 1350153 ◽  
Author(s):  
DRIS BOUBAA ◽  
ALAKABHA DATTA ◽  
MURUGESWARAN DURAISAMY ◽  
SHAABAN KHALIL
Keyword(s):  
Standard Model ◽  
Supersymmetric Standard Model ◽  
Minimal Supersymmetric Standard Model ◽  
Neutral Current ◽  
Higgs Sector ◽  
New Physics ◽  
Flavor Changing ◽  
Clear Sign ◽  
Flavor Changing Neutral Current ◽  
Extended Higgs Sector

The observation of [Formula: see text] at present experiments would be a clear sign of new physics. In this paper, we calculate this process in an extended Higgs sector framework where the decay is mediated by the exchange of spin zero particle with flavor changing neutral current couplings. If we identify the scalar with the newly discovered state at LHC with a mass ~125 GeV then we find that, after imposing all experimental constraints, the [Formula: see text] can be as high as ~10-6 and [Formula: see text] can be as high as ~10-7. We also calculate this process in the minimal supersymmetric standard model and find the [Formula: see text] is typically of the order ~10-8.

SEARCH FOR THE DECAY Bs→μ+μ -ϕ IN $p\bar p$ COLLISIONS AT $\sqrt{s} =1.8\, {\rm TeV}$

2001 ◽  
Vol 16 (supp01a) ◽  
pp. 461-463
Author(s):  
◽  
THOMAS SPEER
Keyword(s):  
Confidence Level ◽  
Branching Fraction ◽  
Neutral Current ◽  
Current Decay ◽  
Flavor Changing ◽  
Upper Limit ◽  
Flavor Changing Neutral Current ◽  
Neutral Current Decay

We present a search for the flavor-changing neutral current decay Bs→ μ+μ-ϕ in [Formula: see text] collisions at [Formula: see text], using 91.4 pb-1 of data collected at the Collider Detector at Fermilab (CDF). We find two candicate events for this decay, which is consistent with the background estimate, and set a preliminary upper limit on the branching fraction of ℬ(Bs → μ+ μ-ϕ)<4.2 · 10-5 at a 90% confidence level.

An investigation into the lepton flavor changing neutral current at a Z-factory

2010 ◽  
Vol 53 (11) ◽  
pp. 1957-1960
Author(s):  
XiaoPeng Li ◽  
Lei Guo ◽  
Liang Han ◽  
WenGan Ma ◽  
RenYou Zhang
Keyword(s):  
Neutral Current ◽  
Lepton Flavor ◽  
Flavor Changing ◽  
Flavor Changing Neutral Current
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