scholarly journals Search for new light vector boson using J/Ψ at BESIII and Belle II

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Kayoung Ban ◽  
Yongsoo Jho ◽  
Youngjoon Kwon ◽  
Seong Chan Park ◽  
Seokhee Park ◽  
...  
Keyword(s):  
Vector Boson ◽  
Mass Range ◽  
Search Strategies ◽  
Boson Mass ◽  
The Third ◽  
Beam Pipe ◽  
Light Vector ◽  
Signal Region ◽  
Belle Ii ◽  
Displaced Vertex

Abstract We investigate various search strategies for light vector boson X in $$ \mathcal{O} $$ O (10) MeV mass range using J/Ψ associated channels at BESIII and Belle II: (i) J/Ψ → ηcX with 1010J/Ψs at BESIII, (ii) J/Ψ(ηc + X) + $$ \mathrm{\ell}\overline{\mathrm{\ell}} $$ ℓ ℓ ¯ production at Belle II, and (iii) J/Ψ + X with the displaced vertex in X → e+e− decay are analyzed and the future sensitivities at Belle II with 50 ab−1 luminosity are comprehensively studied. By requiring the displaced vertex to be within the beam pipe, the third method results in nearly background-free analysis, and the vector boson-electron coupling and the vector boson mass can be probed in the unprecedented range, 10−4 ≤ |εe| ≤ 10−3 and 9 MeV ≤ mX ≤ 100MeV with 50 ab−1 at Belle II. This covers the favored signal region of 8Be* anomaly recently reported by Atomki experiment with mX ≃ 17 MeV.

scholarly journals Review of physics results from the Tevatron: Higgs boson physics

2015 ◽  
Vol 30 (06) ◽  
pp. 1541006 ◽  
Author(s):  
Thomas R. Junk ◽  
Aurelio Juste
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Vector Boson ◽  
Branching Ratio ◽  
Gluon Fusion ◽  
Mass Range ◽  
Higgs Bosons ◽  
Boson Mass ◽  
Decay Modes ◽  
The Standard Model

We review the techniques and results of the searches for the Higgs boson performed by the two Tevatron collaborations, CDF and DØ. The Higgs boson predicted by the Standard Model was sought in the mass range 90 GeV < mH < 200 GeV in all main production modes at the Tevatron: gluon–gluon fusion, WH and ZH associated production, vector boson fusion, and [Formula: see text] production, and in five main decay modes: [Formula: see text], H→τ+τ-, H→WW(*), H→ZZ(*) and H→γγ. An excess of events was seen in the [Formula: see text] searches consistent with a Standard Model Higgs boson with a mass in the range 115 GeV < mH < 135 GeV . Assuming a Higgs boson mass of mH = 125 GeV , studies of Higgs boson properties were performed, including measurements of the product of the cross section times the branching ratio in various production and decay modes, constraints on Higgs boson couplings to fermions and vector bosons, and tests of spin and parity. We also summarize the results of searches for supersymmetric Higgs bosons, and Higgs bosons in other extensions of the Standard Model.

CONSEQUENCES OF A HYPOTHETICAL LIGHT VECTOR BOSON IN NUCLEAR DECAYS

1987 ◽  
Vol 02 (03) ◽  
pp. 159-162 ◽  
Author(s):  
A. SCHÄFER ◽  
B. MÜLLER ◽  
J. REINHARDT
Keyword(s):  
Excited States ◽  
Electric Fields ◽  
Vector Boson ◽  
Mass Range ◽  
Heavy Nuclei ◽  
Light Vector ◽  
Virtual Photons ◽  
Neutral Vector ◽  
Conversion Coefficients ◽  
Strong Electric Fields

We show that a light neutral vector boson in the mass range 1–2 MeV with coupling to three photons would strongly mix with virtual photons in the presence of strong electric fields. Bounds on the strength of the vector boson-three photon interaction can be derived from the measure pair-conversion coefficients for excited states in heavy nuclei. A measurement of the 3γ decay rate of suitable nuclear excited states is suggested.

scholarly journals Long-lived light neutralinos at Belle II

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Sourav Dey ◽  
Claudio O. Dib ◽  
Juan Carlos Helo ◽  
Minakshi Nayak ◽  
Nicolás A. Neill ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Parameter Space ◽  
Rare Decays ◽  
Final States ◽  
Charged Pions ◽  
Belle Ii ◽  
Background Events ◽  
Displaced Vertex

Abstract We consider light neutralinos of mass about 1 GeV, produced from τ lepton rare decays at Belle II, in the context of R-parity-violating (RPV) supersymmetry. With large and clean samples of τ leptons produced at the Belle II experiment, excellent sensitivity to such light neutralinos with the exotic signatures of displaced vertices is expected. We focus on two benchmark scenarios of single RPV operators, $$ {\lambda}_{311}^{\prime }{L}_3{Q}_1{\overline{D}}_1 $$ λ 311 ′ L 3 Q 1 D ¯ 1 and $$ {\lambda}_{312}^{\prime }{L}_3{Q}_1{\overline{D}}_2 $$ λ 312 ′ L 3 Q 1 D ¯ 2 , which induce both the production and decay of the lightest neutralino. For the reconstruction of a displaced vertex, we require at least two charged pions in the final states. We perform Monte-Carlo simulations for both signal and background events, and find that Belle II can explore regions in the parameter space competitive with other probes. In particular, for the $$ {\lambda}_{311}^{\prime } $$ λ 311 ′ scenario, it can put limits up to two orders of magnitude stronger than the current bounds.

scholarly journals Search for dark photons in Higgs boson production via vector boson fusion in proton-proton collisions at $$ \sqrt{s} $$ = 13 TeV

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
A. M. Sirunyan ◽  
◽  
A. Tumasyan ◽  
W. Adam ◽  
T. Bergauer ◽  
...  
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Confidence Level ◽  
Branching Fraction ◽  
Vector Boson ◽  
Boson Mass ◽  
Higgs Boson Mass ◽  
Vector Boson Fusion ◽  
Upper Limit ◽  
The Standard Model

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.

scholarly journals Vector Boson Mass Spectrum from Extra Dimension

2013 ◽  
Vol 04 (07) ◽  
pp. 991-993 ◽  
Author(s):  
Dao Vong Duc ◽  
Nguyen Mong Giao
Keyword(s):  
Mass Spectrum ◽  
Extra Dimension ◽  
Vector Boson ◽  
Boson Mass

Accurate prediction of the Drell-Yan φ∗ η distribution in wide dilepton mass and rapidity ranges in pp collisions through NNLO+N3LL

2021 ◽  
Author(s):  
Kadir Ocalan
Keyword(s):  
Cross Sections ◽  
Good Description ◽  
Neutral Current ◽  
Mass Range ◽  
Theoretical Description ◽  
Distribution Functions ◽  
Boson Mass ◽  
Pp Collisions ◽  
Parton Distribution Functions ◽  
Central Detector

Abstract This paper presents high-accuracy predictions for the differential cross sections as a function of the key observable φ*η of the neutral-current Drell-Yan (DY) dilepton production in proton-proton (pp) collisions. The differential distributions for the φ*η are presented by using the state-of-the-art predictions from the combined calculations of fixed-order perturbative QCD corrections at next-to-next-to-leading order (NNLO) accuracy and resummation of large logarithmic terms at next-to-next-to-leading logarithmic (NNLL) and next-to-NNLL (N3LL) accuracies, i.e., NNLO+NNLL and NNLO+N3LL, respectively. The predicted distributions are reported for a thorough set of the DY dilepton invariant mass mll ranges, spanning a wide kinematic region of 50 < mll< 1000 GeV both near and away from the Z-boson mass peak, and rapidity yll ranges in the central detector acceptance region of |yll| < 2.4. The differential φ*η distributions in the wide mll and yll ranges offer stringent tests to assess the reliability of the predictions, where the mll and yll are closely correlated with the parton distribution functions (PDFs) of the incoming partons. The merged predictions through NNLO+N3LL are observed to provide good description of the 13 TeV pp collision data for the φ*η (including the dilepton transverse momentum pll T as well) distributions in almost the entire mll and yll ranges, apart from the intermediate- to high-φ*η region in the lowest mass range 50–76 GeV which is assessed to constitute a challenge for the presented predictions. The merged predictions at NNLO+N3LL are also reported at 14 TeV for the upcoming high-luminosity running era of the LHC, in which increasing amount of data is expected to require more accurate and precise theoretical description. The most recent PDF models MSHT20 and CT18 are tested for the first time in addition to the NNPDF3.1 exploiting the merged φ*η predictions.

scholarly journals On Sudden Period Changes in Contact Binaries

1980 ◽  
Vol 88 ◽  
pp. 521-526
Author(s):  
Ove Havnes
Keyword(s):  
Mass Range ◽  
Eccentric Orbit ◽  
Third Body ◽  
The Third ◽  
Wide Range ◽  
Contact Binaries

We propose that sudden period jumps in contact binaries can be caused by the action of a third companion in a highly eccentric orbit of small periastron distance. Time jumps as observed are easily reproduced for a wide range in mass of the third body but observations may restrict the possible mass range to less than a few times 0.1 Mo.

scholarly journals Probing μτ flavor-violating solutions for the muon g − 2 anomaly at Belle II

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Syuhei Iguro ◽  
Yuji Omura ◽  
Michihisa Takeuchi
Keyword(s):  
Particle Physics ◽  
Standard Model Prediction ◽  
Mass Range ◽  
Loop Correction ◽  
Lepton Flavor ◽  
Highly Sensitive ◽  
The Standard Model ◽  
Belle Ii ◽  
The One ◽  
Mass Enhancement

Abstract The discrepancy between the measured value and the Standard Model prediction of the muon anomalous magnetic moment is one of the most important issues in the particle physics. It is known that introducing a mediator boson X with the μτ lepton flavor violating (LFV) couplings is one good solution to explain the discrepancy, due to the τ mass enhancement in the one-loop correction. In this paper, we study the signal of this model, i.e. the same-sign leptons, in the Belle II experiment, assuming the flavor-diagonal couplings are suppressed. We show that the Belle II experiment is highly sensitive to the scenario in the mediator mass range of O(1–10) GeV, using the e+e−→ μ±τ∓X → μ±μ±τ∓τ∓ process induced by the X .

Higgs Search with the Compact Muon Solenoid(CMS) detector at the Large Hadron Collider(LHC)

2005 ◽  
Vol 20 (15) ◽  
pp. 3400-3402
Author(s):  
◽  
SATYAKI BHATTACHARYA
Keyword(s):  
Large Hadron Collider ◽  
Standard Model ◽  
Compact Muon Solenoid ◽  
Vector Boson ◽  
Hadron Collider ◽  
Center Of Mass ◽  
Gluon Fusion ◽  
Mass Range ◽  
Early Years ◽  
Higgs Search

The Large Hadron Collider(LHC) is a proton proton collider being built at CERN, Geneva which will collide two 7 TeV proton beams giving a center of mass energy of 14 TeV. The Compact Muon Solenoid (CMS) is a multi-purpose detector at the LHC which is designed to discover the Higgs boson over the mass range of 90 to 1000 GeV. Since LEP searches have put a 95% C.L. lower bound on (standard model) Higgs mass of 114.4 GeV and theory excludes mass above about 1 TeV, CMS should discover the Higgs if it exists. In this paper, we will review CMS's Higgs-discovery potential both in the Standard Model and the Minimal Supersymmetric Standard Model for Higgs bosons produced in gluon-gluon fusion and in vector boson fusion mechanisms. Particular emphasis will be placed on discovery in the early years of running with luminosity of about 2 × 1033cm-2/s.

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