Branching ratio deviations from statistical behavior in core photoionization

AbstractThe Born–Oppenheimer approximation, assuming separable nuclear and electronic motion, is widely adopted for characterizing chemical reactions in a single electronic state. However, the breakdown of the Born–Oppenheimer approximation is omnipresent in chemistry, and a detailed understanding of the non-adiabatic dynamics is still incomplete. Here we investigate the non-adiabatic quenching of electronically excited OH(A2Σ+) molecules by H2 molecules using full-dimensional quantum dynamics calculations for zero total nuclear angular momentum using a high-quality diabatic-potential-energy matrix. Good agreement with experimental observations is found for the OH(X2Π) ro-vibrational distribution, and the non-adiabatic dynamics are shown to be controlled by stereodynamics, namely the relative orientation of the two reactants. The uncovering of a major (in)elastic channel, neglected in a previous analysis but confirmed by a recent experiment, resolves a long-standing experiment–theory disagreement concerning the branching ratio of the two electronic quenching channels.

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Search for π0 decays to invisible particles

Journal of High Energy Physics ◽

10.1007/jhep02(2021)201 ◽

2021 ◽

Vol 2021 (2) ◽

Cited By ~ 1

Author(s):

E. Cortina Gil ◽

◽

A. Kleimenova ◽

E. Minucci ◽

S. Padolski ◽

...

Keyword(s):

Higgs Boson ◽

Standard Model ◽

Confidence Level ◽

Branching Ratio ◽

Standard Model Higgs Boson ◽

Scalar Mixing ◽

Upper Limit ◽

Upper Limits ◽

The Standard Model ◽

Model Independent

Abstract The NA62 experiment at the CERN SPS reports a study of a sample of 4 × 109 tagged π0 mesons from K+ → π+π0(γ), searching for the decay of the π0 to invisible particles. No signal is observed in excess of the expected background fluctuations. An upper limit of 4.4 × 10−9 is set on the branching ratio at 90% confidence level, improving on previous results by a factor of 60. This result can also be interpreted as a model- independent upper limit on the branching ratio for the decay K+ → π+X, where X is a particle escaping detection with mass in the range 0.110–0.155 GeV/c2 and rest lifetime greater than 100 ps. Model-dependent upper limits are obtained assuming X to be an axion-like particle with dominant fermion couplings or a dark scalar mixing with the Standard Model Higgs boson.

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Statistical behavior of fast hashing of variable length test strings

ACM SIGIR Forum ◽

10.1145/101306.101311 ◽

1990 ◽

Vol 24 (3) ◽

pp. 62-71 ◽

Cited By ~ 1

Author(s):

Jacques Savoy

Keyword(s):

Variable Length ◽

Statistical Behavior

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Influence of spatial exclusion on the statistical behavior of attached eddies

Physical Review Fluids ◽

10.1103/physrevfluids.1.022401 ◽

2016 ◽

Vol 1 (2) ◽

Cited By ~ 10

Author(s):

Charitha M. de Silva ◽

James D. Woodcock ◽

Nicholas Hutchins ◽

Ivan Marusic

Keyword(s):

Statistical Behavior ◽

Spatial Exclusion ◽

Attached Eddies

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Disentangling QCD and new physics in D → πℓ+ℓ−

Journal of High Energy Physics ◽

10.1007/jhep04(2021)158 ◽

2021 ◽

Vol 2021 (4) ◽

Author(s):

Aoife Bharucha ◽

Diogo Boito ◽

Cédric Méaux

Keyword(s):

Standard Model ◽

Branching Ratio ◽

Branching Ratios ◽

New Physics ◽

Operator Product ◽

Beyond The Standard Model ◽

Spectral Functions ◽

The Standard Model ◽

Model Independent ◽

Weak Annihilation

Abstract In this paper we consider the decay D+ → π+ℓ+ℓ−, addressing in particular the resonance contributions as well as the relatively large contributions from the weak annihilation diagrams. For the weak annihilation diagrams we include known results from QCD factorisation at low q2 and at high q2, adapting the existing calculation for B decays in the Operator Product Expansion. The hadronic resonance contributions are obtained through a dispersion relation, modelling the spectral functions as towers of Regge-like resonances in each channel, as suggested by Shifman, imposing the partonic behaviour in the deep Euclidean. The parameters of the model are extracted using e+e− → (hadrons) and τ → (hadrons) + ντ data as well as the branching ratios for the resonant decays D+ → π+R(R → ℓ+ℓ−), with R = ρ, ω, and ϕ. We perform a thorough error analysis, and present our results for the Standard Model differential branching ratio as a function of q2. Focusing then on the observables FH and AFB, we consider the sensitivity of this channel to effects of physics beyond the Standard Model, both in a model independent way and for the case of leptoquarks.

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NEW PHYSICS UPPER BOUND ON THE BRANCHING RATIO OF Bs → l+l-γ

Modern Physics Letters A ◽

10.1142/s0217732307021901 ◽

2007 ◽

Vol 22 (18) ◽

pp. 1319-1328 ◽

Cited By ~ 4

Author(s):

ASHUTOSH KUMAR ALOK ◽

S. UMA SANKAR

Keyword(s):

Upper Bound ◽

Axial Vector ◽

Branching Ratio ◽

New Physics ◽

Large Contribution ◽

Beyond The Standard Model ◽

Standard Model Expectation ◽

Model Expectation ◽

The Standard Model ◽

Large Enhancement

We consider the effect of new physics on the branching ratio of Bs → l+l-γ where l = e, μ. If the new physics is of the form scalar/pseudoscalar, then it makes no contribution to Bs → l+l-γ, unlike in the case of Bs → l+l-, where it can potentially make a very large contribution. If the new physics is in the form of vector/axial-vector operators, then the present data on B → (K, K*) l+l- does not allow a large enhancement for B(Bs → l+l- γ). If the new physics is in the form of tensor/pseudotensor operators, then the data on B → (K, K*) l+l- gives no useful constraint but the data on B → K* γ does. Here again, a large enhancement of B(Bs → l+l-γ), much beyond the Standard Model expectation, is not possible. Hence, we conclude that the present data on b → s transitions allow a large boost in B(Bs → l+l-) but not in B(Bs → l+l-γ).

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