scholarly journals New physics in the third family and its effect on low-energy data

1999 ◽  
Vol 61 (1) ◽  
Author(s):  
Ehab Malkawi ◽  
C.-P. Yuan
Keyword(s):  
New Physics ◽  
Low Energy ◽  
Energy Data ◽  
The Third

scholarly journals LOW ENERGY DATA AND A MODEL OF FLAVOR MIXING

1999 ◽  
Vol 14 (22) ◽  
pp. 1487-1496 ◽  
Author(s):  
EHAB MALKAWI ◽  
C.-P. YUAN
Keyword(s):  
B Mesons ◽  
Low Energy ◽  
Boson Mass ◽  
Energy Data ◽  
The Third ◽  
Quark Sector ◽  
Flavor Changing ◽  
Heavy Gauge Boson ◽  
Flavor Mixing ◽  
Gauge Boson Mass

We consider a model in which the third family fermions are subjected to an SU(2) interaction different from the first two family fermions. Constrained by the Z-pole data, the heavy gauge boson mass is bounded from below to be about 1.7 TeV at the 2σ level. In this model, the flavor mixing between τ and μ can be so large that [Formula: see text] and Br (τ→μμμ) provide a better constraint than the LEP/SLC data in some region of parameter space. Furthermore, flavor-changing neutral currents are unavoidable in the quark sector of the model. Significant effects to the [Formula: see text] mixing and the rare decays of the K and B mesons, such as [Formula: see text], [Formula: see text], Bs→τ+τ-, μ+μ- and Bs,d→μ±τ∓, are expected.

Realizing Stable High‐Performance and Low‐Energy‐Loss Ternary Photovoltaics through Judicious Selection of the Third Component

Solar RRL ◽  
2021 ◽  
pp. 2100450
Author(s):  
Bing-Huang Jiang ◽  
Yi-Peng Wang ◽  
Yu-Wei Su ◽  
Jia-Fu Chang ◽  
Chu-Chen Chueh ◽  
...  
Keyword(s):  
Energy Loss ◽  
High Performance ◽  
Low Energy ◽  
The Third ◽  
Selection Of

scholarly journals The low-energy effective theory of axions and ALPs

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Martin Bauer ◽  
Matthias Neubert ◽  
Sophie Renner ◽  
Marvin Schnubel ◽  
Andrea Thamm
Keyword(s):  
High Energy ◽  
New Physics ◽  
Mass Scale ◽  
Low Energy ◽  
Effective Theory ◽  
Loop Order ◽  
Flavor Changing ◽  
Effective Lagrangian ◽  
Anomalous Dimensions ◽  
Pseudoscalar Mesons

Abstract Axions and axion-like particles (ALPs) are well-motivated low-energy relics of high-energy extensions of the Standard Model, which interact with the known particles through higher-dimensional operators suppressed by the mass scale Λ of the new-physics sector. Starting from the most general dimension-5 interactions, we discuss in detail the evolution of the ALP couplings from the new-physics scale to energies at and below the scale of electroweak symmetry breaking. We derive the relevant anomalous dimensions at two-loop order in gauge couplings and one-loop order in Yukawa interactions, carefully considering the treatment of a redundant operator involving an ALP coupling to the Higgs current. We account for one-loop (and partially two-loop) matching contributions at the weak scale, including in particular flavor-changing effects. The relations between different equivalent forms of the effective Lagrangian are discussed in detail. We also construct the effective chiral Lagrangian for an ALP interacting with photons and light pseudoscalar mesons, pointing out important differences with the corresponding Lagrangian for the QCD axion.

scholarly journals Flavour Anomalies in a U(1) SUSY Extension of the SM

Symmetry ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 191
Author(s):  
Alexander Bednyakov ◽  
Alfiia Mukhaeva
Keyword(s):  
Standard Model ◽  
Parameter Space ◽  
Gauge Boson ◽  
New Physics ◽  
Low Energy ◽  
Effective Theory ◽  
The Standard Model ◽  
Meson Mixing ◽  
Additional Anomaly ◽  
Lepton Flavour

Flavour anomalies have attracted a lot of attention over recent years as they provide unique hints for possible New Physics. Here, we consider a supersymmetric (SUSY) extension of the Standard Model (SM) with an additional anomaly-free gauge U(1) group. The key feature of our model is the particular choice of non-universal charges to the gauge boson Z′, which not only allows a relaxation of the flavour discrepancies but, contrary to previous studies, can reproduce the SM mixing matrices both in the quark and lepton sectors. We pay special attention to the latter and explicitly enumerate all parameters relevant for our calculation in the low-energy effective theory. We find regions in the parameter space that satisfy experimental constraints on meson mixing and LHC Z′ searches and can alleviate the flavour anomalies. In addition, we also discuss the predictions for lepton-flavour violating decays B+→K+μτ and B+→K+eτ.

Photoproduction of Gravitational Radiation in Static Electromagnetic Fields. Radiative Corrections

1975 ◽  
Vol 53 (20) ◽  
pp. 2315-2320 ◽  
Author(s):  
G. Papini ◽  
S. -R. Valluri
Keyword(s):  
Cross Section ◽  
Gravitational Radiation ◽  
Low Energy ◽  
Radiative Corrections ◽  
Third Order ◽  
The Third ◽  
Relativistic Approximation ◽  
Effective Lagrangian ◽  
Charge Renormalization ◽  
Made In

The radiative corrections of second and third order for the process of photoproduction of gravitons in Coulomb and magnetic dipole fields have been calculated.All divergences have been removed either by charge renormalization or regularization. No approximations have been made in the calculation of the second order cross section. In the third order calculation only the extreme relativistic approximation is given. The forms of the effective Lagrangian, corresponding to the low energy approximations have been determined.

scholarly journals Exploring $$\hbox {CE}\nu \hbox {NS}$$ with NUCLEUS at the Chooz nuclear power plant

2019 ◽  
Vol 79 (12) ◽  
Author(s):  
G. Angloher ◽  
F. Ardellier-Desages ◽  
A. Bento ◽  
L. Canonica ◽  
A. Erhart ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Sensitivity Study ◽  
New Physics ◽  
Low Energy ◽  
Cryogenic Detectors ◽  
Reduction Techniques ◽  
Low Energies ◽  
Nuclear Recoils

AbstractCoherent elastic neutrino–nucleus scattering ($$\hbox {CE}\nu \hbox {NS}$$CEνNS) offers a unique way to study neutrino properties and to search for new physics beyond the Standard Model. Nuclear reactors are promising sources to explore this process at low energies since they deliver large fluxes of anti-neutrinos with typical energies of a few MeV. In this paper, a new-generation experiment to study $$\hbox {CE}\nu \hbox {NS}$$CEνNS is described. The NUCLEUS experiment will use cryogenic detectors which feature an unprecedentedly low-energy threshold and a time response fast enough to be operated under above-ground conditions. Both sensitivity to low-energy nuclear recoils and a high event rate tolerance are stringent requirements to measuring $$\hbox {CE}\nu \hbox {NS}$$CEνNS of reactor anti-neutrinos. A new experimental site, the Very-Near-Site (VNS), at the Chooz nuclear power plant in France is described. The VNS is located between the two 4.25 $$\hbox {GW}_{\mathrm {th}}$$GWth reactor cores and matches the requirements of NUCLEUS. First results of on-site measurements of neutron and muon backgrounds, the expected dominant background contributions, are given. In this paper a preliminary experimental set-up with dedicated active and passive background reduction techniques and first background estimations are presented. Furthermore, the feasibility to operate the detectors in coincidence with an active muon veto at shallow overburden is studied. The paper concludes with a sensitivity study pointing out the physics potential of NUCLEUS at the Chooz nuclear power plant.

scholarly journals p-Wave Strength in the Low-energy 7Li(p,?0)8Be Cross Section

1995 ◽  
Vol 48 (5) ◽  
pp. 813 ◽  
Author(s):  
FC Barker
Keyword(s):  
Angular Distribution ◽  
Shell Model ◽  
Cross Section ◽  
Low Energy ◽  
P Wave ◽  
Model Calculations ◽  
Energy Data

Recent fits to low-energy 7Li(p, "Yo)8Be angular distribution and analysing power data suggested a large p-wave strength. It is shown that acceptable fits to the data can be obtained by attributing the p-wave Ml contributions to the tails of the 17 �64 and 18 �15 MeV 1+ levels of 8Be, with p-wave strengths much less than those obtained previously, but only if some of the spectroscopic amplitudes have signs opposite to those suggested by shell model calculations and/or a fit to higher-energy data.

scholarly journals Constraints on the charged currents in general neutrino interactions with sterile neutrinos

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
Tong Li ◽  
Xiao-Dong Ma ◽  
Michael A. Schmidt
Keyword(s):  
Field Theory ◽  
Effective Field Theory ◽  
Neutral Current ◽  
New Physics ◽  
Effective Field ◽  
Lepton Number ◽  
Low Energy ◽  
Electroweak Scale ◽  
Sterile Neutrinos ◽  
Neutrino Interactions

Abstract In this work we investigate the implication of low-energy precision measurements on the quark-lepton charged currents in general neutrino interactions with sterile neutrinos in effective field theories. The physics in low-energy measurements is described by the low-energy effective field theory extended with sterile neutrinos (LNEFT) defined below the electroweak scale. We also take into account renormalization group running and match the LNEFT onto the Standard Model (SM) effective field theory with sterile neutrinos (SMNEFT) to constrain new physics (NP) above the electroweak scale. The most sensitive low-energy probes are from leptonic decays of pseudoscalar mesons and hadronic tau lepton decays in terms of precise decay branching fractions, the lepton flavor universality and the Cabibbo-Kobayashi-Maskawa (CKM) unitarity. We also consider other constraints including nuclear beta decay. The constraints on charged current operators are generally stronger than the ones for quark-neutrino neutral current operators. We find that the most stringent bounds on the NP scale of lepton-number-conserving and lepton- number-violating operators in SMNEFT are 74 (110) TeV and 9.8 (13) TeV, respectively, for the operators with down (strange) quark.

scholarly journals Rb, Rc and New Physics: An Updated Model Independent Analysis

1997 ◽  
Vol 12 (04) ◽  
pp. 723-742 ◽  
Author(s):  
P. Bamert
Keyword(s):  
Standard Model ◽  
Neutral Current ◽  
New Physics ◽  
Low Energy ◽  
Coupling Constant ◽  
A Value ◽  
Independent Analysis ◽  
The Standard Model ◽  
Necessary And Sufficient ◽  
Do So

We analyze LEP and SLC data from the 1995 Summer Conferences as well as from low energy neutral current experiments for signals of new physics. The reasons for doing this are twofold: first to explain the deviations from the Standard Model observed in Rb and Rc and second to constrain nonstandard contributions to couplings of the Z0 boson to all fermions and to the oblique parameters. We do so by comparing the data with the Standard Model as well as with a number of test hypotheses concerning the nature of the new physics. These include nonstandard [Formula: see text]-, [Formula: see text]- and [Formula: see text]-couplings as well as the couplings of the Z0 to fermions of the entire first, second and third generations and universal corrections to all up- and down-type quark couplings (as can arise see for example in Z' mixing models). We find that nonstandard [Formula: see text] couplings are both necessary and sufficient to explain the data and in particular the Rb anomaly. It is not possible to explain Rb, Rc and a value of the strong coupling constant consistent with low energy determinations invoking only nonstandard [Formula: see text]- and [Formula: see text]-couplings. To do so one has to have also new physics contributions to the [Formula: see text] or universal corrections to all [Formula: see text] couplings.

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