scholarly journals Decay of standard model-like Higgs boson H_1→Z_γ in the simplest 3-3-1 model

2021 ◽  
Vol 6 (19) ◽  
pp. 140-143
Author(s):  
Tho Vu Quang ◽  
Hong Trinh Thi ◽  
Thanh Truong Tien

The decays of the Higgs boson H_1→Z_γ are discussed in the simplest 3-3-1 model. Analytic formulas for one-loop contributions were constructed using well-known general results. We will show that new particles predicted by this simplest 3-3-1 model may gice significant effects to this decay of the standard model-like Higgs boson. From numerical investigation, some details and properties of this decay are presented. the may be useful for comparing with the experimental results that will be detected in the future.

2004 ◽  
Vol 19 (06) ◽  
pp. 822-834
Author(s):  
E. PEREZ

An overview of recent experimental results on searches for new phenomena at the LEP, HERA and Tevatron high energy colliders is presented, including in particular new results obtained from the analysis of the Run II data at the Tevatron. No significant evidence for physics beyond the Standard Model has been found and limits at the 95% confidence level have been set on the mass and couplings of several new particles. The complementarity between the different experiments is discussed, as well as future prospects for ongoing and future experiments.


2005 ◽  
Vol 20 (15) ◽  
pp. 3294-3296
Author(s):  
◽  
Yoshio Ishizawa

We present searches for new particles decaying into [Formula: see text] and produced in association with W± bosons in [Formula: see text] collisions at [Formula: see text]. The searches focus on the Standard Model Higgs boson or Technicolor particle decaying into [Formula: see text] using approximately 162 pb-1 of the dataset accumulated by the Collider Detector at Fermilab. The number of events and mass distribution are consistent with the Standard Model expectations and we set a 95% confidence level upper limit on the production cross section times branching ratio as a function of the new particle mass.


2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
E. Cortina Gil ◽  
◽  
A. Kleimenova ◽  
E. Minucci ◽  
S. Padolski ◽  
...  

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.


2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
A. M. Sirunyan ◽  
◽  
A. Tumasyan ◽  
W. Adam ◽  
T. Bergauer ◽  
...  

Abstract A search is presented for a Higgs boson that is produced via vector boson fusion and that decays to an undetected particle and an isolated photon. The search is performed by the CMS collaboration at the LHC, using a data set corresponding to an integrated luminosity of 130 fb−1, recorded at a center-of-mass energy of 13 TeV in 2016–2018. No significant excess of events above the expectation from the standard model background is found. The results are interpreted in the context of a theoretical model in which the undetected particle is a massless dark photon. An upper limit is set on the product of the cross section for production via vector boson fusion and the branching fraction for such a Higgs boson decay, as a function of the Higgs boson mass. For a Higgs boson mass of 125 GeV, assuming the standard model production rates, the observed (expected) 95% confidence level upper limit on the branching fraction is 3.5 (2.8)%. This is the first search for such decays in the vector boson fusion channel. Combination with a previous search for Higgs bosons produced in association with a Z boson results in an observed (expected) upper limit on the branching fraction of 2.9 (2.1)% at 95% confidence level.


2021 ◽  
Vol 812 ◽  
pp. 135980
Author(s):  
G. Aad ◽  
B. Abbott ◽  
D.C. Abbott ◽  
A. Abed Abud ◽  
K. Abeling ◽  
...  

2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
Henning Bahl ◽  
Philip Bechtle ◽  
Sven Heinemeyer ◽  
Judith Katzy ◽  
Tobias Klingl ◽  
...  

Abstract The $$ \mathcal{CP} $$ CP structure of the Higgs boson in its coupling to the particles of the Standard Model is amongst the most important Higgs boson properties which have not yet been constrained with high precision. In this study, all relevant inclusive and differential Higgs boson measurements from the ATLAS and CMS experiments are used to constrain the $$ \mathcal{CP} $$ CP -nature of the top-Yukawa interaction. The model dependence of the constraints is studied by successively allowing for new physics contributions to the couplings of the Higgs boson to massive vector bosons, to photons, and to gluons. In the most general case, we find that the current data still permits a significant $$ \mathcal{CP} $$ CP -odd component in the top-Yukawa coupling. Furthermore, we explore the prospects to further constrain the $$ \mathcal{CP} $$ CP properties of this coupling with future LHC data by determining tH production rates independently from possible accompanying variations of the $$ t\overline{t}H $$ t t ¯ H rate. This is achieved via a careful selection of discriminating observables. At the HL-LHC, we find that evidence for tH production at the Standard Model rate can be achieved in the Higgs to diphoton decay channel alone.


2001 ◽  
Vol 508 (3-4) ◽  
pp. 225-236 ◽  
Author(s):  
M. Acciarri ◽  
P. Achard ◽  
O. Adriani ◽  
M. Aguilar-Benitez ◽  
J. Alcaraz ◽  
...  

1994 ◽  
Vol 63 (3) ◽  
pp. 417-425 ◽  
Author(s):  
Eilam Gross ◽  
Bernd A. Kniehl ◽  
Gustavo Wolf

Author(s):  
S.K. Abdullayev ◽  
◽  
E.Sh. Omarova ◽  

Within the framework of the Standard Model, the radiative decay channel of the Higgs boson into fermion-antifermion pair is investigated: H Þ` ff γ. Taking into account the fermion and W -boson loop diagrams an analytical expression for the decay width is obtained, the circular polarization of the γ-quanta is studied in dependence of the angle θ and invariant mass of the fermion pair.


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