scholarly journals On the effective lifetime of Bs → μμγ

2021 ◽  
Vol 2021 (12) ◽  
Author(s):  
Alexandre Carvunis ◽  
Francesco Dettori ◽  
Shireen Gangal ◽  
Diego Guadagnoli ◽  
Camille Normand

Abstract We consider the $$ {B}_s^0 $$ B s 0 → μ+μ−γ effective lifetime, and the related CP-phase sensitive quantity $$ {A}_{{\Delta \Gamma}_s}^{\mu \mu \gamma} $$ A ΔΓ s μμγ , as a way to obtain qualitatively new insights on the current B-decay discrepancies. Through a fit comparing pre- to post-Moriond-2021 data we identify a few theory benchmark scenarios addressing these discrepancies, and featuring large CP violation in addition. We then explore the possibility of telling apart these scenarios with $$ {A}_{{\Delta \Gamma}_s}^{\mu \mu \gamma} $$ A ΔΓ s μμγ , once resonance-modeling and form-factor uncertainties are taken into account. We do so in both regions of low and high invariant di-lepton mass-squared q2. For low q2, we show how to shape the integration range in order to reduce the impact of the ϕ-resonance modelling on the $$ {A}_{{\Delta \Gamma}_s}^{\mu \mu \gamma} $$ A ΔΓ s μμγ prediction. For high q2, we find that the corresponding pollution from broad-charmonium resonances has a surprisingly small effect on $$ {A}_{{\Delta \Gamma}_s}^{\mu \mu \gamma} $$ A ΔΓ s μμγ . This is due to a number of cancellations, that can be traced back to the complete dominance of semi-leptonic operator contributions for high q2 — at variance with low q2 — and to $$ {A}_{{\Delta \Gamma}_s}^{\mu \mu \gamma} $$ A ΔΓ s μμγ behaving like a ratio-of-amplitudes observable. Our study suggests that $$ {A}_{{\Delta \Gamma}_s}^{\mu \mu \gamma} $$ A ΔΓ s μμγ is — especially at high q2 — a potentially valuable probe of short-distance CP-violating effects in the very same Wilson coefficients that are associated to current b → s discrepancies. Its discriminating power, however, relies on progress in form-factor uncertainties. Interestingly, high q2 is the region where $$ {B}_s^0 $$ B s 0 → μ+μ−γ is already being accessed experimentally, and the region where form factors are more accessible through non-perturbative QCD methods.

2018 ◽  
Vol 192 ◽  
pp. 00027
Author(s):  
Adolfo Guevara ◽  
Pablo Roig ◽  
Juan José Sanz Cillero

We have studied the P → γ⋆ γ⋆ form factor in Resonance Chiral Theory, with P = π0; η, η', to compute the contribution of the pseudoscalar pole to the hadronic light-by-light piece of the anomalous magnetic moment of the muon. In this work we allow the leading U(3) chiral symmetry breaking terms, obtaining the most general expression for the form factor of order O(m2P). The parameters of the Effective Field Theory are obtained by means of short distance constraints on the form factor and matching with the expected behavior from QCD. Those parameters that cannot be fixed in this way are fitted to experimental determinations of the form factor within the spacelike momentum region of the virtual photon. Chiral symmetry relations among the transition form factors for π0, η and η' allow for a simultaneous fit to experimental data for the three mesons. This shows an inconsistency between the BaBar π0 data and the rest of the experimental inputs. Thus, we find a total pseudoscalar pole contribution of aP,HLbLη = (8:47 ± 0:16) · 10-10 for our best fit (neglecting the BaBar π0 data). Also, a preliminary rough estimate of the impact of NLO in 1=NC corrections and higher vector multiplets (asym) enlarges the uncertainty up to aP,HLbLη = (8:47 ± 0:16stat ± 0:09NC +0:5 -0:0asym).


Author(s):  
Talbot C. Imlay

This chapter examines the post-war efforts of European socialists to reconstitute the Socialist International. Initial efforts to cooperate culminated in an international socialist conference in Berne in February 1919 at which socialists from the two wartime camps met for the first time. In the end, however, it would take four years to reconstitute the International with the creation of the Labour and Socialist International (LSI) in 1923. That it took so long to do so is a testimony to the impact of the Great War and to the Bolshevik revolution. Together, these two seismic events compelled socialists to reconsider the meaning and purpose of socialism. The search for answers sparked prolonged debates between and within the major parties, profoundly reconfiguring the pre-war world of European socialism. One prominent stake in this lengthy process, moreover, was the nature of socialist internationalism—both its content and its functioning.


2020 ◽  
pp. 152483802097968
Author(s):  
Sarah Lockwood ◽  
Carlos A. Cuevas

Traditionally, the literature has sought to understand the impact of racial minority status and trauma as it relates to interpersonal violence, domestic violence, and sexual assault. What has not been as extensively reviewed and summarized is how racially or ethnically motivated hate crimes impact the mental health of minorities—particularly Latinx/Hispanic groups. This review aims to summarize the current body of literature on the intersection of race-motivated hate crime and trauma responses within Latinx community. To do so, the theoretical foundation for this inquiry will build from a race-based trauma perspective. Specifically, this review connects existing frameworks for race and trauma and integrates literature that examines Latinx or Hispanic populations that have experienced discrimination, bias, or hate crime as a result of their identity or perceived identity. The importance of situating bias or hate events within the trauma literature stems from a lack of overall formal evaluation of these events, and how these occurrences are historically overlooked as a traumatic stressor. The findings of this review suggest that (1) experiencing racially motivated victimization can cause adverse mental and physical health outcomes in Latinxs and (2) currently, there is only one study that has examined the impact of hate crime on Latinxs in the United States. This leaves the field with unanswered questions about the impact of hate crime victimization among Latinxs, which is an ever-growing area in need of attention.


Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1271
Author(s):  
Humberto. J. Prado-Galiñanes ◽  
Rosario Domingo

Industries are nowadays not only expected to produce goods and provide services, but also to do this sustainably. What qualifies a company as sustainable implies that its activities must be defined according to the social and ecological responsibilities that are meant to protect the society and the environment in which they operate. From now on, it will be necessary to consider and measure the impact of industrial activities on the environment, and to do so, one key parameter is the carbon footprint. This paper demonstrates the utility of the LCI as a tool for immediate application in industries. Its application shall facilitate decision making in industries while choosing amongst different scenarios to industrialize a certain product with the lowest environmental impact possible. To achieve this, the carbon footprint of a given product was calculated by applying the LCI method to several scenarios that differed from each other only in the supply-chain model. As a result of this LCI calculation, the impact of the globalization of a good’s production was quantified not only financially, but also environmentally. Finally, it was concluded that the LCI/LCA methodology can be considered as a fundamental factor in the new decision-making strategy that sustainable companies must implement while deciding on the business and industrial plan for their new products and services.


1968 ◽  
Vol 46 (10) ◽  
pp. S377-S380 ◽  
Author(s):  
A. A. Petrukhin ◽  
V. V. Shestakov

The cross section for the muon bremsstrahlung process is calculated as a function of the nuclear form factor in the Born approximation following the Bethe and Heitler theory. The influence of the nuclear form factor is greater than that taken by Christy and Kusaka. The simple analytical expression for the effect of the screening of the atomic electrons is found. The influence of a decrease in the cross section upon the interpretation of some experimental results is estimated.


2001 ◽  
Vol 38 (04) ◽  
pp. 1033-1054 ◽  
Author(s):  
Liudas Giraitis ◽  
Piotr Kokoszka ◽  
Remigijus Leipus

The paper studies the impact of a broadly understood trend, which includes a change point in mean and monotonic trends studied by Bhattacharyaet al.(1983), on the asymptotic behaviour of a class of tests designed to detect long memory in a stationary sequence. Our results pertain to a family of tests which are similar to Lo's (1991) modifiedR/Stest. We show that both long memory and nonstationarity (presence of trend or change points) can lead to rejection of the null hypothesis of short memory, so that further testing is needed to discriminate between long memory and some forms of nonstationarity. We provide quantitative description of trends which do or do not fool theR/S-type long memory tests. We show, in particular, that a shift in mean of a magnitude larger thanN-½, whereNis the sample size, affects the asymptotic size of the tests, whereas smaller shifts do not do so.


2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Y. Ünal ◽  
Ulf-G. Meißner

Abstract We report on the calculation of the CP-violating form factor F3 and the corresponding electric dipole moment for charmed baryons in the spin-1/2 sector generated by the QCD θ-term. We work in the framework of covariant baryon chiral perturbation theory within the extended-on-mass-shell renormalization scheme up to next-to-leading order in the chiral expansion.


1980 ◽  
Vol 58 (1) ◽  
pp. 48-62 ◽  
Author(s):  
R. D. Graves ◽  
B. A. Lamers ◽  
Anton Nagl ◽  
H. Überall ◽  
V. Devanathan ◽  
...  

The available experimental data for the form factors of the T = 1 levels in 16O, obtained from electron scattering at low (Darmstadt), medium (Tohoku), and high momentum transfer (Stanford), are interpreted by the generalized Helm model. This phenomenological model reduces the form factor description of each level to the listing of a few physical parameters, i.e., the radius and smearing width of the transition densities of charge (current) and magnetization, and their corresponding strength constants. Its parameters having been determined by the form factor fits, the model may then be used to predict the results of other medium energy processes; this is done here for the photoproduction of charged pions and for muon capture in16O.


2011 ◽  
Vol 13 (2) ◽  
pp. 135-144 ◽  
Author(s):  
Gavin E. Oxburgh ◽  
Coral J. Dando

PurposeThe purpose of this paper is to discuss two distinct but interrelated areas, namely witness/victim and suspect interviewing, and to argue that both must continue to evolve, suggest how they might do so, and that this process must be driven by emergent theory and contemporary empirical research.Design/methodology/approachThe paper outlines the impact of psychological theory and empirical research to investigative interviewing in recent decades.FindingsIt is argued that in order to stay ahead of the game, the field of investigative interviewing (suspect and witness) must continue to evolve in such a manner that not only protects and fosters the important practitioner/academic relationship, but also ensures that future directions are driven by empirical research, with recourse to emergent theory.Originality/valueThe paper outlines the impact of psychological theory and empirical research on investigative interviewing and the consequent enhancement of the interviewing of both suspected offenders and witnesses. The paper demonstrates that working closely together academic research can make a difference, and influence law, policy decisions and training guidelines in order to improve practice.


1999 ◽  
Vol 551 (1-2) ◽  
pp. 3-40 ◽  
Author(s):  
W Hollik ◽  
J.I Illana ◽  
S Rigolin ◽  
C Schappacher ◽  
D Stöckinger

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