Bounds on fourth-generation fermion masses in the standard model

1985 ◽  
Vol 29 (1) ◽  
pp. 41-43 ◽  
Author(s):  
K. S. Babu ◽  
Ernest Ma
Keyword(s):  
Standard Model ◽  
Fourth Generation ◽  
Fermion Masses ◽  
The Standard Model

Seesaw fermion masses in the standard model

1989 ◽  
Vol 39 (1) ◽  
pp. 351-353 ◽  
Author(s):  
Subhash Rajpoot
Keyword(s):  
Standard Model ◽  
Fermion Masses ◽  
The Standard Model

scholarly journals Constraints on a Fourth Generation of Fermions from Higgs Boson Searches

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Alexander Lenz
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Higgs Doublet ◽  
Current Status ◽  
Fourth Generation ◽  
The Past ◽  
The Standard Model

We review the past and current status of the extension of the standard model (SM) by a fourth generation of fermions. In particular the new results for Higgs boson searches at the LHC and at Tevatron exclude the possibility of having simply a perturbative fourth generation of fermions with one Higgs doublet (SM4). We also briefly mention more complicated extensions of the SM4, which are not yet excluded, like adding in addition another Higgs doublet to the SM4.

scholarly journals COMPLETE STUDY OF THE SEMILEPTONIC B TO $K_2^*(1430)$ DECAYS IN THE STANDARD MODEL WITH FOURTH GENERATION

2012 ◽  
Vol 27 (25) ◽  
pp. 1250149 ◽  
Author(s):  
MUHAMMAD JUNAID ◽  
MUHAMMAD JAMIL ASLAM ◽  
ISHTIAQ AHMED
Keyword(s):  
Standard Model ◽  
Form Factors ◽  
Experimental Information ◽  
Fourth Generation ◽  
Final State ◽  
Cp Asymmetry ◽  
The Standard Model ◽  
Complete Study ◽  
Lepton Polarization ◽  
State Formula

The [Formula: see text] decays are analyzed in the standard model (SM) extended to fourth generation of quarks (SM4). The decay rate, forward–backward asymmetry, lepton polarization asymmetries, the helicity fractions of the final state [Formula: see text] meson and CP asymmetry are discussed using the form factors calculated in the light-cone sum rules (LCSR) approach. We utilized the constraints on different fourth generation parameters obtained from the experimental information on K, B and D decays and from their recent searches at the ATLAS and CMS experiments to explore their impact on the [Formula: see text] decays. We find that the values of above mentioned physical observables deviate significantly from their minimal SM predications. In the present study, we will also perform the analysis of CP asymmetry in [Formula: see text] decays within SM4, which is one of the most interesting observable in the study of SM4.

scholarly journals The Fourth Generation t-prime in Extensions of the Standard Model

2010 ◽  
Author(s):  
Erin De Pree ◽  
Gardner Marshall ◽  
Marc Sher ◽  
George Alverson ◽  
Pran Nath ◽  
...  
Keyword(s):  
Standard Model ◽  
Fourth Generation ◽  
The Standard Model

scholarly journals Comments on gauge anomalies at dimension-six in the Standard Model Effective Field Theory

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Quentin Bonnefoy ◽  
Luca Di Luzio ◽  
Christophe Grojean ◽  
Ayan Paul ◽  
Alejo N. Rossia
Keyword(s):  
Field Theory ◽  
Standard Model ◽  
Effective Field Theory ◽  
Effective Field ◽  
Goldstone Bosons ◽  
Fermion Masses ◽  
Higher Dimensional ◽  
The Standard Model ◽  
Gauge Anomalies ◽  
Working Out

Abstract We study whether higher-dimensional operators in effective field theories, in particular in the Standard Model Effective Field Theory (SMEFT), can source gauge anomalies via the modification of the interactions involved in triangle diagrams. We find no evidence of such gauge anomalies at the level of dimension-6 operators that can therefore be chosen independently to each others without spoiling the consistency of SMEFT, at variance with recent claims. The underlying reason is that gauge-invariant combinations of Goldstone bosons and massive gauge fields are allowed to couple to matter currents which are not conserved. We show this in a toy model by computing the relevant triangle diagrams, as well as by working out Wess-Zumino terms in the bosonic EFT below all fermion masses. The same approach applies directly to the Standard Model both at the renormalisable level, providing a convenient and unusual way to check that the SM is anomaly free, as well as at the non-renormalisable level in SMEFT.

ARE THERE CP-VIOLATING PROCESSES IN THE STANDARD MODEL WITHOUT LOOP CORRECTIONS?

1989 ◽  
Vol 04 (09) ◽  
pp. 821-829 ◽  
Author(s):  
M. NOWAKOWSKI ◽  
A. PILAFTSIS
Keyword(s):  
Cp Violation ◽  
Standard Model ◽  
Fourth Generation ◽  
Interesting Aspect ◽  
Scattering Process ◽  
The Standard Model ◽  
New Type ◽  
The Masses ◽  
Cp Asymmetries

In an effort to find new CP-violating phenomena in the Standard Model, we present a new type of CP asymmetries which have interesting theoretical features. We investigate the possibility of CP nonconservation manifesting itself at Born level. We find that such processes indeed exist provided the reaction under consideration includes two W’s coupled to two different flavors and an additional boson (γ, g, Z0, H0). A second interesting aspect of these phenomena is the property that the CP-violation appears in a scattering process as opposed to that in a decay of a particle. We estimate the values of these CP asymmetries within the Standard Model with three and four generations and show that the effect is, in principle, measurable if the masses of the quarks belonging to the fourth generation are large.

Sign in / Sign up

Export Citation Format

Share Document