$H^0\bar ff$ AND $Z\bar ff$ INTERACTIONS IN THEEFFECTIVE LAGRANGIAN APPROACH

1996 ◽  
Vol 11 (27) ◽  
pp. 4921-4929 ◽  
Author(s):  
J. M. HERNÁNDEZ ◽  
O. A. SAMPAYO ◽  
J. J. TOSCANO
Keyword(s):  
Standard Model ◽  
New Physics ◽  
Lagrangian Approach ◽  
Low Energy ◽  
Tree Level ◽  
Beyond The Standard Model ◽  
Fermionic Operators ◽  
The Standard Model

We study possible effects induced by decoupled physics beyond the standard model on the decays [Formula: see text] and [Formula: see text] in the framework of effective Lagrangians. We consider only those dimension 6 [ SU L (2) × U Y (1)]-invariant fermionic operators that may be generated at tree level by the underlying physics. Using electroweak data, we get constraints on low energy new physics contributions to the partial widths [Formula: see text], including leptonic FCNC effects. We also discuss the underlying physics effects induced on [Formula: see text] of light fermions. In particular, we find a remarkable enhancement of the ēe, ūu and [Formula: see text] channels.

ONE LOOP-INDUCED WZH COUPLING IN THE TWO HIGGS DOUBLET MODEL

1989 ◽  
Vol 04 (28) ◽  
pp. 2757-2766 ◽  
Author(s):  
THOMAS G. RIZZO
Keyword(s):  
Standard Model ◽  
Higgs Doublet ◽  
New Physics ◽  
Tree Level ◽  
Beyond The Standard Model ◽  
The Standard Model ◽  
Charged Higgs ◽  
Doublet Model ◽  
The One ◽  
Two Higgs Doublet Model

Although absent at the tree level in models with only doublet and singlet Higgs representations, the WZH coupling can be induced at the one-loop level. We examine the size of this induced coupling in the two Higgs doublet model due to fermion as well as Higgs/gauge boson loops. Such couplings could provide a new mechanism for charged Higgs production at colliders and are ‘backgrounds’ to new physics beyond the Standard Model. We find, however, that these couplings are very weak for all regions of the parameter space explored.

scholarly journals DETERMINING αs FROM MEASUREMENTS AT Z: HOW NATURE PROMPTS US ABOUT NEW PHYSICS

1995 ◽  
Vol 10 (07) ◽  
pp. 605-613 ◽  
Author(s):  
M. SHIFMAN
Keyword(s):  
Standard Model ◽  
New Physics ◽  
Low Energy ◽  
Beyond The Standard Model ◽  
The Standard Model ◽  
Standard Deviations ◽  
The One

The value of αs (Mz) emerging from the so-called global fits based mainly on the data at the Z peak (and assuming the standard model) is three standard deviations higher than the one stemming from the low-energy phenomenology. The corresponding value of Λ QCD is very large, ~500 MeV, and is incompatible with crucial features of QCD. If persists, the discrepancy should be interpreted as due to contributions to the Z-quark-antiquark vertices which go beyond the standard model.

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.

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.

SEARCH FOR NEW PHYSICS IN eμX DATA AT THE TEVATRON USING SLEUTH: A QUASI-MODEL-INDEPENDENT SEARCH STRATEGY FOR NEW PHYSICS

2001 ◽  
Vol 16 (supp01b) ◽  
pp. 888-890
Author(s):  
◽  
BRUCE KNUTESON
Keyword(s):  
Standard Model ◽  
Search Strategy ◽  
New Physics ◽  
Beyond The Standard Model ◽  
Final States ◽  
Final State ◽  
The Standard Model ◽  
Model Independent

We present a quasi-model-independent search for physics beyond the standard model. We define final states to be studied, and construct a rule that identifies a set of variables appropriate for any particular final state. A new algorithm ("Sleuth") searches for regions of excess in the space of those variables and quantifies the significance of any detected excess. After demonstrating the sensititvity of the method, we apply it to the semi-inclusive channel eμX collected in ≈108 pb -1 of [Formula: see text] collisions at [Formula: see text] at the DØ experiment at the Fermilab Tevatron. We find no evidence of new high pT physics in this sample.

CAN WE RELATE TIME-REVERSAL VIOLATION TO NEW PHYSICS PROCESSES IN WEAK HADRONIC DECAYS?

2013 ◽  
Vol 22 (03) ◽  
pp. 1330006 ◽  
Author(s):  
Z. J. AJALTOUNI ◽  
E. DI SALVO
Keyword(s):  
Experimental Data ◽  
Cp Violation ◽  
Standard Model ◽  
Time Reversal ◽  
Review Paper ◽  
New Physics ◽  
Hadronic Decays ◽  
Beyond The Standard Model ◽  
Weak Decays ◽  
The Standard Model

This review paper stresses the possible connection between time-reversal violation and new physics processes beyond the standard model. In particular, this violation is proposed as an alternative to CP violation in the search for such unkown processes. Emphasis is put on the weak decays of heavy hadrons, especially beauty ones. Specific methods for extracting useful parameters from experimental data are elaborated in order to test TR symmetry. These methods could be used successfully in the analysis of the LHC data.

scholarly journals One Loop Corrections to Decay \(\tau\rightarrow \mu\gamma\) in Economical 3-3-1 Model

2015 ◽  
Vol 25 (2) ◽  
pp. 113
Author(s):  
Truong Trong Thuc ◽  
Le Tho Hue ◽  
Dinh Phan Khoi ◽  
Nguyen Thanh Phong
Keyword(s):  
Standard Model ◽  
New Physics ◽  
Beyond The Standard Model ◽  
Lepton Flavor ◽  
Unitary Gauge ◽  
The Standard Model ◽  
Charged Leptons

Lepton flavor violating (cLFV) decays of charged leptons such as \(\tau\rightarrow \mu\gamma\), \(\tau\rightarrow e\gamma\), \(\mu\rightarrow e\gamma\),..., are now the subjects of experiments as signals of new Physics beyond the Standard Model (SM). In the limit of the unitary gauge, we prove that contributions from one loop corrections to the above decays are very small in the framework of the economical 3-3-1 model.

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