scholarly journals Lepton-flavor-violating decays of the SM-like Higgs boson $h\rightarrow e_ie_j$, and $e_i \rightarrow e_j\, \gamma $ in a flipped 3-3-1 model

2020 ◽  
Vol 2020 (4) ◽  
Author(s):  
T T Hong ◽  
H T Hung ◽  
H H Phuong ◽  
L T T Phuong ◽  
L T Hue
Keyword(s):  
Higgs Boson ◽  
Branching Ratio ◽  
High Energy ◽  
Branching Ratios ◽  
The Other ◽  
Experimental Limit ◽  
Lepton Flavor ◽  
The Standard Model ◽  
Charged Leptons ◽  
O 10

Abstract In the framework of the flipped 3-3-1 model introduced recently [R. M. Fonseca and M. Hirsch, J. High Energy Phys. 1608, 003 (2016)], the lepton-flavor-violating (LFV) decay $\mu \rightarrow 3e$ was predicted to have a large branching ratio (Br) close to the recent experimental limit. We will show that the Br of LFV decays of the standard-model-like (SM-like) Higgs boson decays (LFVHD) Br$(h\rightarrow e_ae_b)$ may also be large. Namely, Br$(h\rightarrow \mu\tau,e\tau)$ can reach values of $\mathcal{O}(10^{-4}){-}\mathcal{O}(10^{-5})$, which will reach the upcoming experimental sensitivities. On the other hand, for LFV decays of charged leptons (cLFV) $(e_b\rightarrow e_a\gamma)$, the branching ratios are well below experimental bounds.

scholarly journals Lepton Flavor Violation in Economical 3-3-1 Model with Neutrino Singlets

2019 ◽  
Vol 29 (1) ◽  
pp. 87
Author(s):  
Le Tho Hue ◽  
Dinh Phan Khoi ◽  
Hoang Hanh Phuong ◽  
Ha Thanh Hung
Keyword(s):  
Higgs Boson ◽  
Decay Rates ◽  
Higgs Bosons ◽  
Boson Mass ◽  
Lepton Flavor Violation ◽  
Lepton Flavor ◽  
Flavor Violation ◽  
Charged Higgs ◽  
Charged Leptons ◽  
O 10

Lepton flavor violating (LFV) decays of charged leptons \(\mu\rightarrow e\gamma\)  and SM-like Higgs boson \(h\rightarrow \mu\tau\) are discussed in the framework of the  economical 3-3-1 model  adding three additional singlets neutrinos (E331\(X_R\)). We will show that the appearance of new neutrinos and charged Higgs bosons in this model can result in interesting regions of the parameter space, which satisfy  the recent experimental bound of \(Br(\mu\rightarrow e\gamma)\)  as well as give large \(Br(h\rightarrow \mu\tau)\geq \mathcal{O}(10^{-7})\) . In these regions,  the charged Higgs boson mass lies within the range of \(2-3\) TeV. Our results show that the LFV decays are important channels to distinguish the E331\(X_R\)  and the original economical (E331) models, which predicts suppressed LFV decay rates.

NON-STANDARD HIGGS BOSON AND THE DECAY KL→π0l+l−

1988 ◽  
Vol 03 (17) ◽  
pp. 1677-1682 ◽  
Author(s):  
M.I. DOBROLIUBOV ◽  
A. YU. IGNATIEV
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Branching Ratio ◽  
Branching Ratios ◽  
Upper Bounds ◽  
The Standard Model

We investigate various mechanisms of enhancement of the branching ratios of the decay KL→π0l+l− as compared to the predictions of the Standard Model. We propose a model with several Higgs doublets, which contains a Higgs boson with nearly equal couplings to e+e− and µ+µ− pairs. In this model, the branching ratio BR (KL→π0e+e−, π0µ+µ−) can be close to the present experimental upper bounds.

scholarly journals Search for π0 decays to invisible particles

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
E. Cortina Gil ◽  
◽  
A. Kleimenova ◽  
E. Minucci ◽  
S. Padolski ◽  
...  
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Confidence Level ◽  
Branching Ratio ◽  
Standard Model Higgs Boson ◽  
Scalar Mixing ◽  
Upper Limit ◽  
Upper Limits ◽  
The Standard Model ◽  
Model Independent

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.

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 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.

Study of the semileptonic Bc → ηcτ−v̄τ decay in W′ model

2021 ◽  
Author(s):  
S. Mahata ◽  
P. Maji ◽  
S. Biswas ◽  
S. Sahoo
Keyword(s):  
Standard Model ◽  
Branching Ratio ◽  
New Physics ◽  
Experimental Results ◽  
Lepton Flavor ◽  
The Standard Model ◽  
Text Model

Recently, many discrepancies between the Standard Model (SM) predictions and experimental results have been found in [Formula: see text] quark transitions. Motivated by these discrepancies, we investigated the semileptonic [Formula: see text] decay in [Formula: see text] model. In this paper, we have estimated different decay observables such as branching ratio, lepton flavor universality (LFU) ratio [Formula: see text] and forward–backward asymmetry in the SM as well as in the [Formula: see text] model. In [Formula: see text] model, we find significant deviations from the SM for the observables except for the forward–backward asymmetry. This deviation gives us a possible indication of new physics (NP).

scholarly journals PRECISION MASS DETERMINATION OF THE HIGGS BOSON AT PHOTON–PHOTON COLLIDERS

2000 ◽  
Vol 15 (16) ◽  
pp. 2605-2611 ◽  
Author(s):  
TOMOMI OHGAKI
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Higgs Mass ◽  
Statistical Error ◽  
High Energy ◽  
Boson Mass ◽  
Total Width ◽  
Mass Determination ◽  
The Standard Model

We demonstrate a measurement of the Higgs boson mass by the method of energy scanning at photon–photon colliders, using the high energy edge of the photon spectrum. With an integrated luminosity of 50 fb-1 it is possible to measure the standard model Higgs mass to within 110 MeV in photon–photon collisions for mh=100 GeV. As for the total width of the Higgs boson, the statistical error ΔΓh/Γh SM=0.06 is expected for mh=100 GeV, if both Γ(h→γγ) and [Formula: see text] are fixed at the predicted standard model value.

scholarly journals Higgs boson production cross-section measurements and their EFT interpretation in the $$4\ell $$ decay channel at $$\sqrt{s}=$$13 TeV with the ATLAS detector

2020 ◽  
Vol 80 (10) ◽  
Author(s):  
G. Aad ◽  
◽  
B. Abbott ◽  
D. C. Abbott ◽  
A. Abed Abud ◽  
...  
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Cross Section ◽  
Decay Channel ◽  
Branching Ratio ◽  
Proton Collision ◽  
Boson Production ◽  
Theory Approach ◽  
Higgs Boson Production ◽  
The Standard Model

AbstractHiggs boson properties are studied in the four-lepton decay channel (where lepton = e, $$\mu $$ μ ) using 139 $$\hbox {fb}^{-1}$$ fb - 1 of proton–proton collision data recorded at $$\sqrt{s}=$$ s = 13 TeV by the ATLAS experiment at the Large Hadron Collider. The inclusive cross-section times branching ratio for $$H\rightarrow ZZ^*$$ H → Z Z ∗ decay is measured to be $$1.34 \pm 0.12$$ 1.34 ± 0.12  pb for a Higgs boson with absolute rapidity below 2.5, in good agreement with the Standard Model prediction of $$1.33 \pm 0.08$$ 1.33 ± 0.08  pb. Cross-sections times branching ratio are measured for the main Higgs boson production modes in several exclusive phase-space regions. The measurements are interpreted in terms of coupling modifiers and of the tensor structure of Higgs boson interactions using an effective field theory approach. Exclusion limits are set on the CP-even and CP-odd ‘beyond the Standard Model’ couplings of the Higgs boson to vector bosons, gluons and top quarks.

scholarly journals THE HIGGS PUZZLE: EXPERIMENT AND THEORY

2002 ◽  
Vol 17 (23) ◽  
pp. 3300-3317
Author(s):  
FABIO ZWIRNER
Keyword(s):  
Higgs Boson ◽  
High Energy ◽  
Experimental Information ◽  
Electroweak Symmetry Breaking ◽  
Electroweak Symmetry ◽  
Supersymmetric Extension ◽  
Light Higgs Boson ◽  
Open Questions ◽  
The Standard Model ◽  
Spatial Dimensions

The present experimental and theoretical knowledge of the physics of electroweak symmetry breaking is reviewed. Data still favor a light Higgs boson, of a kind that can be comfortably accommodated in the Standard Model or in its Minimal Supersymmetric extension, but exhibit a non-trivial structure that leaves some open questions. The available experimental information may still be reconciled with the absence of a light Higgs boson, but the price to pay looks excessive. Recent theoretical ideas, linking the weak scale with the size of possible extra spatial dimensions, are briefly mentioned. It is stressed once more that experiments at high-energy colliders, such as the Tevatron and the LHC, are the crucial tool for eventually solving the Higgs puzzle.

scholarly journals THE SEARCH FOR, AND DISCOVERY OF, THE HIGGS BOSON AT CMS

2013 ◽  
Vol 28 (02) ◽  
pp. 1330003 ◽  
Author(s):  
DANIEL GREEN
Keyword(s):  
Higgs Boson ◽  
High Energy Physics ◽  
Hadron Collider ◽  
Higgs Field ◽  
High Energy ◽  
Higgs Particle ◽  
The Standard Model ◽  
Future Data ◽  
Low Mass ◽  
Energy Physics

The Higgs field was first proposed almost 50 years ago. Twenty years ago the tools needed to discover the Higgs boson, the large hadron collider and the CMS and ATLAS experiments, were initiated. Data taking was begun in 2010 and culminated in the announcement of the discovery of a "Higgs-like" boson on 4 July 2012. This discovery completes the Standard Model (SM) of high energy physics, if it is indeed the hypothesized SM Higgs particle. Future data taking will explore the properties of the new 125 GeV particle to see if it has all the attributes of an SM Higgs and to explore the mechanism that maintains its "low" mass.

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