scholarly journals Dark Photon Searches at BESIII

2018 ◽  
Vol 46 ◽  
pp. 1860046 ◽  
Author(s):  
Dayong Wang
Keyword(s):  
Degrees Of Freedom ◽  
New Physics ◽  
Beyond The Standard Model ◽  
Gauge Bosons ◽  
Data Set ◽  
Decay Modes ◽  
Dark Photon ◽  
The Standard Model ◽  
New Type ◽  
Low Mass

Many models beyond the Standard Model, motivated by the recent astrophysical anomalies, predict a new type of weak-interacting degrees of freedom. Typical models include the possibility of the low-mass dark gauge bosons of a few GeV and thus making them accessible at the BESIII experiment running at the tau-charm region. The BESIII has recently searched such dark bosons in several decay modes using the high statistics data set collected at charmonium resonaces. This talk will summarize the recent BESIII results of these dark photon searches and related new physics studies.

scholarly journals STUDY OF THE ELECTROMAGNETIC TRANSITIONS J/ψ → P l+l- AND PROBE DARK PHOTON

2012 ◽  
Vol 27 (38) ◽  
pp. 1250223 ◽  
Author(s):  
JINLIN FU ◽  
HAI-BO LI ◽  
XIAOSHUAI QIN ◽  
MAO-ZHI YANG
Keyword(s):  
Form Factor ◽  
Internal Conversion ◽  
Massive Particle ◽  
Lepton Pairs ◽  
Data Set ◽  
Decay Modes ◽  
Electromagnetic Structure ◽  
Dark Photon ◽  
The Standard Model ◽  
Shed Light

We study the electromagnetic Dalitz decay modes of J/ψ → P l+l- (P = π0, η or η′). In these decays, the lepton pairs are formed by internal conversion of an intermediate virtual photon with invariant mass ml+l-. Study of the effective-mass spectrum of the l+l- will shed light on the dynamic transition form factor [Formula: see text], which characterizes the electromagnetic structure arising at the vertex of the transition J/ψ to pseudoscalars. We also discuss the direct productions of a GeV scale vector U boson in these processes J/ψ → PU (U → l+l-). It is responsible for mediating a new U(1)d interaction, as recently exploited in the context of weakly interacting massive particle dark matter. In this paper, we firstly use the usual pole approximation for the form factor to estimate the decay rate of J/ψ → P l+l- in the Standard Model. Then the reach of searching for the dark photon is estimated. We suggest that these Dalitz decays can be used to search for the light U boson in the BESIII experiment with a huge J/ψ data set.

SEARCHES FOR NEW PHYSICS AT HIGH ENERGY COLLIDERS

2005 ◽  
Vol 20 (22) ◽  
pp. 5164-5173 ◽  
Author(s):  
BEATE HEINEMANN
Keyword(s):  
Standard Model ◽  
Extra Dimensions ◽  
High Energy ◽  
New Physics ◽  
Standard Model Background ◽  
Beyond The Standard Model ◽  
Gauge Bosons ◽  
Model Background ◽  
The Standard Model

Recent searches for physics beyond the Standard Model at high energy colliders are presented. The main focus is on searches for supersymmetry, extra dimensions and new gauge bosons. In all search analyses the data are found to agree well with the Standard Model background expectation and no evidence for contributions from physics beyond the Standard Model is found. The data are thus used to place limits on new physics scenarios.

scholarly journals ANOMALOUS HIGGS COUPLINGS

1999 ◽  
Vol 14 (20) ◽  
pp. 3121-3156 ◽  
Author(s):  
M. C. GONZALEZ-GARCIA
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Higgs Doublet ◽  
New Physics ◽  
Boson Production ◽  
Gauge Bosons ◽  
Effective Interactions ◽  
Decay Modes ◽  
Effective Lagrangian ◽  
The Standard Model

We review the effects of new effective interactions on Higgs-boson phenomenology. New physics in the electroweak bosonic sector is expected to induce additional interactions between the Higgs doublet field and the electroweak gauge bosons, leading to anomalous Higgs couplings as well as anomalous gauge-boson self-interactions. Using a linearly realized SU (2)L× U (1)Y invariant effective Lagrangian to describe the bosonic sector of the Standard Model, we review the effects of the new effective interactions on the Higgs-boson production rates and decay modes. We summarize the results from searches for the new Higgs signatures induced by the anomalous interactions in order to constrain the scale of new physics, in particular at CERN LEP and Fermilab Tevatron colliders.

scholarly journals On the τ flavor of the cosmic neutrino flux

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Yasaman Farzan
Keyword(s):  
Dark Matter ◽  
Degrees Of Freedom ◽  
Neutrino Flux ◽  
High Energy ◽  
New Physics ◽  
Beyond The Standard Model ◽  
New Era ◽  
The Standard Model ◽  
Cosmic Neutrino ◽  
Standard Picture

Abstract Observation of high energy cosmic neutrinos by ICECUBE has ushered in a new era in exploring both cosmos and new physics beyond the Standard Model (SM). In the standard picture, although mostly νμ and νe are produced in the source, oscillation will produce ντen route. Certain beyond SM scenarios, like interaction with ultralight DM can alter this picture. Thus, the flavor composition of the cosmic neutrino flux can open up the possibility of exploring certain beyond the SM scenarios that are inaccessible otherwise. We show that the τ flavor holds a special place among the neutrino flavors in elucidating new physics. Interpreting the two anomalous events observed by ANITA as ντ events makes the tau flavor even more intriguing. We study how the detection of the two tau events by ICECUBE constrains the interaction of the neutrinos with ultralight dark matter and discuss the implications of this interaction for even higher energy cosmic neutrinos detectable by future radio telescopes such as ARA, ARIANNA and GRAND. We also revisit the 3 + 1 neutrino scheme as a solution to the two anomalous ANITA events and clarify a misconception that exists in the literature about the evolution of high energy neutrinos in matter within the 3 + 1 scheme with a possibility of scattering off nuclei. We show that the existing bounds on the flux of ντ with energy of EeV rules out this solution for the ANITA events. We show that the 3 + 1 solution can be saved from both this bound and from the bound on the extra relativistic degrees of freedom in the early universe by turning on the interaction of neutrinos with ultralight dark matter.

scholarly journals Dark photon bounds in the dark EFT

2021 ◽  
Vol 2021 (12) ◽  
Author(s):  
Daniele Barducci ◽  
Enrico Bertuzzo ◽  
Giovanni Grilli di Cortona ◽  
Gabriel M. Salla
Keyword(s):  
Degrees Of Freedom ◽  
Dipole Interaction ◽  
Effective Field ◽  
Gauge Bosons ◽  
Abelian Gauge ◽  
Dark Photon ◽  
Mixing Parameter ◽  
The Standard Model ◽  
New States ◽  
Strength Tensor

Abstract Dark photons are massive abelian gauge bosons that interact with ordinary photons via a kinetic mixing with the hypercharge field strength tensor. This theory is probed by a variety of different experiments and limits are set on a combination of the dark photon mass and kinetic mixing parameter. These limits can however be strongly modified by the presence of additional heavy degrees of freedom. Using the framework of dark effective field theory, we study how robust are the current experimental bounds when these new states are present. We focus in particular on the possible existence of a dark dipole interaction between the Standard Model leptons and the dark photon. We show that, under certain assumptions, the presence of a dark dipole modifies existing supernovæ bounds for cut-off scales up to $$ \mathcal{O} $$ O (10–100 TeV). On the other hand, terrestrial experiments, such as LSND and E137, can probe cut-off scales up to $$ \mathcal{O} $$ O (3 TeV). For the latter experiment we highlight that the bound may extend down to vanishing kinetic mixing.

scholarly journals The CKM unitarity problem: a trace of new physics at the TeV scale?

2020 ◽  
Vol 80 (2) ◽  
Author(s):  
Benedetta Belfatto ◽  
Revaz Beradze ◽  
Zurab Berezhiani
Keyword(s):  
Standard Model ◽  
Decay Constant ◽  
New Physics ◽  
Muon Decay ◽  
Beyond The Standard Model ◽  
Neutron Lifetime ◽  
Gauge Bosons ◽  
Family Symmetry ◽  
Ckm Matrix ◽  
The Standard Model

Abstract After the recent high precision determinations of $$V_{us}$$Vus and $$V_{ud}$$Vud, the first row of the CKM matrix shows more than $$4\sigma $$4σ deviation from unitarity. Two possible scenarios beyond the Standard Model can be investigated in order to fill the gap. If a 4th non-sequential quark $$b'$$b′ (a vector-like weak isosinglet) participates in the mixing, with $$\vert V_{ub'} \vert \sim 0.04$$|Vub′|∼0.04, then its mass should be no more than 6 TeV or so. A different solution can come from the introduction of the gauge horizontal family symmetry $$SU(3)_\ell $$SU(3)ℓ acting between the lepton families and spontaneously broken at the scale of about 6 TeV. Since the gauge bosons of this symmetry contribute to muon decay in interference with Standard Model, the Fermi constant is slightly smaller than the muon decay constant so that unitarity is recovered. Also the neutron lifetime problem, that is about $$4\sigma $$4σ discrepancy between the neutron lifetimes measured in beam and trap experiments, is discussed in the light of the these determinations of the CKM matrix elements.

MEASUREMENTS OF THE PROPERTIES OF THE Z BOSON, THE STANDARD MODEL AND BEYOND

1991 ◽  
Vol 06 (02) ◽  
pp. 199-216
Author(s):  
THOMAS G. RIZZO
Keyword(s):  
Standard Model ◽  
Z Boson ◽  
New Physics ◽  
Beyond The Standard Model ◽  
Gauge Bosons ◽  
The Standard Model

Recent measurements of the properties of the Z boson at the SLC and LEP colliders are compared with the radiatively corrected predictions of the standard model as well as several classes of models containing additional gauge bosons. The possible evidence for new physics beyond the standard model is discussed.

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 NEW PHYSICS UPPER BOUND ON THE BRANCHING RATIO OF Bs → l+l-γ

2007 ◽  
Vol 22 (18) ◽  
pp. 1319-1328 ◽  
Author(s):  
ASHUTOSH KUMAR ALOK ◽  
S. UMA SANKAR
Keyword(s):  
Upper Bound ◽  
Axial Vector ◽  
Branching Ratio ◽  
New Physics ◽  
Large Contribution ◽  
Beyond The Standard Model ◽  
Standard Model Expectation ◽  
Model Expectation ◽  
The Standard Model ◽  
Large Enhancement

We consider the effect of new physics on the branching ratio of Bs → l+l-γ where l = e, μ. If the new physics is of the form scalar/pseudoscalar, then it makes no contribution to Bs → l+l-γ, unlike in the case of Bs → l+l-, where it can potentially make a very large contribution. If the new physics is in the form of vector/axial-vector operators, then the present data on B → (K, K*) l+l- does not allow a large enhancement for B(Bs → l+l- γ). If the new physics is in the form of tensor/pseudotensor operators, then the data on B → (K, K*) l+l- gives no useful constraint but the data on B → K* γ does. Here again, a large enhancement of B(Bs → l+l-γ), much beyond the Standard Model expectation, is not possible. Hence, we conclude that the present data on b → s transitions allow a large boost in B(Bs → l+l-) but not in B(Bs → l+l-γ).

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