scholarly journals Improved predictions of the standard model and the detection of new physics in neutron beta decay

2002 ◽  
Vol 546 (3-4) ◽  
pp. 247-252 ◽  
Author(s):  
A García ◽  
J.L García-Luna
Keyword(s):  
Standard Model ◽  
Beta Decay ◽  
New Physics ◽  
Neutron Beta Decay ◽  
The Standard Model

scholarly journals Tests of the standard model in neutron beta decay with polarized electrons and unpolarized neutrons and protons

2019 ◽  
Vol 99 (5) ◽  
Author(s):  
A. N. Ivanov ◽  
R. Höllwieser ◽  
N. I. Troitskaya ◽  
M. Wellenzohn ◽  
Ya. A. Berdnikov
Keyword(s):  
Standard Model ◽  
Beta Decay ◽  
Polarized Electrons ◽  
Neutron Beta Decay ◽  
The Standard Model

scholarly journals NoMoS: An R × B drift momentum spectrometer for beta decay studies

2019 ◽  
Vol 219 ◽  
pp. 04003 ◽  
Author(s):  
Daniel Moser ◽  
Hartmut Abele ◽  
Joachim Bosina ◽  
Harald Fillunger ◽  
Torsten Soldner ◽  
...  
Keyword(s):  
Standard Model ◽  
Angular Correlation ◽  
Beta Decay ◽  
Particle Physics ◽  
Correlation Coefficients ◽  
New Physics ◽  
Interference Term ◽  
Free Neutron ◽  
The Standard Model ◽  
Momentum Spectra

The beta decay of the free neutron provides several probes to test the Standard Model of particle physics as well as to search for extensions thereof. Hence, multiple experiments investigating the decay have already been performed, are under way or are being prepared. These measure the mean lifetime, angular correlation coefficients or various spectra of the charged decay products (proton and electron). NoMoS, the neutron decay products mo___mentum spectrometer, presents a novel method of momentum spectroscopy: it utilizes the R ×B drift effect to disperse charged particles dependent on their momentum in an uniformly curved magnetic field. This spectrometer is designed to precisely measure momentum spectra and angular correlation coefficients in free neutron beta decay to test the Standard Model and to search for new physics beyond. With NoMoS, we aim to measure inter alia the electron-antineutrino correlation coefficient a and the Fierz interference term b with an ultimate precision of Δa/a < 0.3% and Δb < 10−3 respectively. In this paper, we present the measurement principles, discuss measurement uncertainties and systematics, and give a status update.

NEUTRINOLESS DOUBLE BETA DECAY EXPERIMENTS

2019 ◽  
pp. 32-39
Author(s):  
N.S. Rumyantseva ◽  
K.N. Gusev
Keyword(s):  
Standard Model ◽  
Beta Decay ◽  
Electroweak Interaction ◽  
Neutrinoless Double Beta Decay ◽  
New Physics ◽  
Lepton Number ◽  
Double Beta Decay ◽  
The Standard Model ◽  
New Generation ◽  
Lepton Number Violating

Neutrinoless double beta decay is a lepton number violating process which is not allowed in the Standard Model (SM) of the electroweak interaction. The discovery of this process will be an unambiguous confirmation of the existence of New Physics outside the SM. At this moment many experiments are being conducted aimed at searching for neutrinoless double beta decay on various isotopes (76Ge, 136Xe, 130Te, 100Mo, etc.). The paper presents a brief overview of the results of some current projects, such as GERDA, MAJORANA, KamLAND-Zen, EXO-200, CUORE and SuperNEMO, and plans for creating a new generation experiments.

scholarly journals Theoretical description of the neutron beta decay in the standard model at the level of 10−5

2021 ◽  
Vol 104 (3) ◽  
Author(s):  
A. N. Ivanov ◽  
R. Höllwieser ◽  
N. I. Troitskaya ◽  
M. Wellenzohn ◽  
Ya. A. Berdnikov
Keyword(s):  
Standard Model ◽  
Beta Decay ◽  
Theoretical Description ◽  
Neutron Beta Decay ◽  
The Standard Model

scholarly journals Standard Model prediction of the Bc lifetime

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Jason Aebischer ◽  
Benjamín Grinstein
Keyword(s):  
Standard Model ◽  
Model Prediction ◽  
Strange Quark ◽  
Standard Model Prediction ◽  
New Physics ◽  
Operator Product ◽  
Special Focus ◽  
Third Order ◽  
Clear Cut ◽  
The Standard Model

Abstract Applying an operator product expansion approach we update the Standard Model prediction of the Bc lifetime from over 20 years ago. The non-perturbative velocity expansion is carried out up to third order in the relative velocity of the heavy quarks. The scheme dependence is studied using three different mass schemes for the $$ \overline{b} $$ b ¯ and c quarks, resulting in three different values consistent with each other and with experiment. Special focus has been laid on renormalon cancellation in the computation. Uncertainties resulting from scale dependence, neglecting the strange quark mass, non-perturbative matrix elements and parametric uncertainties are discussed in detail. The resulting uncertainties are still rather large compared to the experimental ones, and therefore do not allow for clear-cut conclusions concerning New Physics effects in the Bc decay.

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

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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