scholarly journals Prospects for $$ {B}_c^{+} $$→ τ +ντ at FCC-ee

2021 ◽  
Vol 2021 (12) ◽  
Author(s):  
Yasmine Amhis ◽  
Marie Hartmann ◽  
Clément Helsens ◽  
Donal Hill ◽  
Olcyr Sumensari
Keyword(s):  
Precise Measurement ◽  
Branching Fraction ◽  
New Physics ◽  
Topological Information ◽  
Second Stage ◽  
Boosted Decision Tree ◽  
Tree Algorithms ◽  
Signal Yield ◽  
Event Based ◽  
High Rejection

Abstract This paper presents the prospects for a precise measurement of the branching fraction of the leptonic $$ {B}_c^{+} $$ B c + → τ+ντ decay at the Future Circular Collider (FCC-ee) running at the Z -pole. A detailed description of the simulation and analysis framework is provided. To select signal candidates, two Boosted Decision Tree algorithms are employed and optimised. The first stage suppresses inclusive $$ b\overline{b} $$ b b ¯ , $$ c\overline{c} $$ c c ¯ , and $$ q\overline{q} $$ q q ¯ backgrounds using event-based topological information. A second stage utilises the properties of the hadronic τ+→ π+π+π−$$ \overline{\nu} $$ ν ¯ τ decay to further suppress these backgrounds, and is also found to achieve high rejection for the B+→ τ+ντ background. The number of $$ {B}_c^{+} $$ B c + → τ+ντ candidates is estimated for various Tera-Z scenarios, and the potential precision of signal yield and branching fraction measurements evaluated. The phenomenological impact of such measurements on various New Physics scenarios is also explored.

scholarly journals HEAVY QUARK LIFETIMES, MIXING AND CP VIOLATION

2000 ◽  
Vol 15 (10) ◽  
pp. 1393-1414
Author(s):  
GUY BLAYLOCK
Keyword(s):  
Cp Violation ◽  
Heavy Quark ◽  
Heavy Quark Physics ◽  
Branching Fraction ◽  
New Physics ◽  
Unitarity Triangle ◽  
Lifetime Measurements ◽  
Physics First ◽  
Charm Decay ◽  
Charm Mixing

This paper emphasizes four topics that represent some of the year's highlights in heavy quark physics. First of all, a review is given of charm lifetime measurements and how they lead to better understanding of the mechanisms of charm decay. Secondly, the CLEO collaboration's new search for charm mixing is reported, which significantly extends the search for new physics in that sector. Thirdly, important updates in Bs mixing are summarized, which result in a new limit on ΔMs, and which further constrain the unitarity triangle. Finally, the first efforts to measure CP violation in the B system are discussed. Results are shown for the CDF and ALEPH measurements of sin 2β, as well as the CLEO branching fraction measurements of B→Kπ, ππ, which have implications for future measurements of α.

scholarly journals Search for single production of vectorlike top partners through th channel at the HE-LHC and FCC-hh

2021 ◽  
Vol 81 (7) ◽  
Author(s):  
Xi-Yan Tian ◽  
Liu-Feng Du ◽  
Yao-Bei Liu
Keyword(s):  
Standard Model ◽  
Production Cross ◽  
Branching Fraction ◽  
Hadron Collider ◽  
High Energy ◽  
New Physics ◽  
Beyond The Standard Model ◽  
The Standard Model ◽  
Single Production ◽  
Integrated Luminosity

AbstractThe vectorlike top partners are potential signature of some new physics beyond the Standard Model at the TeV scale. In this paper, we propose to search for the vectorlike T quark with charge 2/3 in the framework of a simplified model where the top partners only couples with the third generation of Standard Model quarks. We investigate the observability for electroweak production of a vectorlike T quark in association with a standard model bottom quark through the process $$pp \rightarrow T\bar{b}j$$ p p → T b ¯ j with the subsequent decay mode of $$T\rightarrow t(\rightarrow b W^+\rightarrow b \ell ^{+} \nu _{\ell })h( \rightarrow \gamma \gamma )$$ T → t ( → b W + → b ℓ + ν ℓ ) h ( → γ γ ) , at the proposed High Energy Large Hadron Collider (HE-LHC) and Future Circular Collider in hadron-hadron mode (FCC-hh) including the realistic detector effects. The 95% confidence level excluded regions and the $$5\sigma $$ 5 σ discovery reach in the parameter plane of $$\kappa _{T}-m_T$$ κ T - m T , are respectively obtained at the HE-LHC with the integrated luminosity of 15 ab$$^{-1}$$ - 1 and the FCC-hh with the integrated luminosity of 30 ab$$^{-1}$$ - 1 . We also analyze the projected sensitivity in terms of the production cross section times branching fraction at the HE-LHC and FCC-hh.

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 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 − .

Study of B̄s → ϕμ+μ− decays in the G(211) model and vector leptoquark model

2017 ◽  
Vol 32 (25) ◽  
pp. 1750155 ◽  
Author(s):  
Shuai-Wei Wang
Keyword(s):  
Standard Model ◽  
Large Deviation ◽  
Branching Fraction ◽  
New Physics ◽  
Decay Process ◽  
Angular Distributions ◽  
The Standard Model ◽  
Lepton Polarization ◽  
Text Model

We study [Formula: see text] decay in the [Formula: see text] model and vector leptoquark model, respectively. We consider the effects of these two new physics (NP) models on some measured physical observables of this decay process, such as the differential branching fraction and the angular distributions. We find that the large deviation of the differential branching fraction between the measurement and the Standard Model (SM) prediction can be explained in these two NP models. However, we found that not all observables of the double-lepton polarization asymmetries are sensitive to the contributions of these NP models.

scholarly journals Probing the Effects of New Physics in B¯⁎→Plν¯l Decays

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Qin Chang ◽  
Jie Zhu ◽  
Na Wang ◽  
Ru-Min Wang
Keyword(s):  
Spin Asymmetry ◽  
Branching Fraction ◽  
New Physics ◽  
Heavy Flavor ◽  
Independent Vector ◽  
Vector Type ◽  
Scalar Type ◽  
The Future ◽  
Significant Divergence ◽  
Model Independent

The significant divergence between the SM predictions and experimental measurements for the ratios, RD(⁎)≡B(B¯→D(⁎)τ-ν¯τ)/B(B¯→D(⁎)l′-ν¯l′) with (l′=e,μ), implies possible hint of new physics in the flavor sector. In this paper, motivated by the “RD(⁎) puzzle” and abundant B⁎ data samples at high-luminosity heavy-flavor experiments in the future, we try to probe possible effects of new physics in the semileptonic B¯u,d,s⁎→Pl-ν¯l  (P=D,Ds,π,K) decays induced by b→(u,c)l-ν¯l transitions in the model-independent vector and scalar scenarios. Using the spaces of NP parameters obtained by fitting to the data of RD and RD⁎, the NP effects on the observables including branching fraction, ratio RP⁎, lepton spin asymmetry, and lepton forward-backward asymmetry are studied in detail. We find that the vector type couplings have large effects on the branching fraction and ratio RP⁎. Meanwhile, the scalar type couplings provide significant contributions to all of the observables. The future measurements of these observables in the B¯⁎→Pl-ν¯l decays at the LHCb and Belle-II could provide a way to crosscheck the various NP solutions to the “RD(⁎) puzzle”.

scholarly journals Resources Planning for Container Terminal in a Maritime Supply Chain Using Multiple Particle Swarms Optimization (MPSO)

Mathematics ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 764 ◽  
Author(s):  
Hsien-Pin Hsu ◽  
Chia-Nan Wang
Keyword(s):  
Supply Chain ◽  
Container Terminal ◽  
Optimal Solution ◽  
Container Terminals ◽  
Particle Swarms ◽  
Scarce Resources ◽  
Second Stage ◽  
Event Based ◽  
Resources Planning ◽  
Multiple Particle

Resources planning is an important task in a supply chain in order to achieve a good result. The better the utilization of resources, especially scarce resources, the better the performance of a supply chain. This research focuses on allocating two scarce resources, i.e., berth and quay cranes (QCs), to ships that call at a container terminal in a maritime supply chain. As global container shipments continue to grow, improving the efficiency of container terminals is important. A two-stage approach is used to find the optimal/near-optimal solution, in which the first stage is devoted to generating alternative ship placement sequences as inputs to the second stage that subsequently employs an event-based heuristic to place ships, resolve overlaps of ships, and assign/adjust QCs so as to develop a feasible solution. For identifying a better approach, various heuristics/metaheuristics, including first-come first-served (FCFS), particle swarm optimization (PSO), improved PSO (PSO2), and multiple PSO (MPSO), have been employed in the first stage, respectively. The experimental results show that combining the MPSO with the event-based heuristic leads to a better result.

Sign in / Sign up

Export Citation Format

Share Document