Search for New Particles Decaying into $b \bar{b}$ Associated with W± Bosons at Tevatron

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.


2020 ◽  
Vol 80 (10) ◽  
Author(s):  
G. Aad ◽  
◽  
B. Abbott ◽  
D. C. Abbott ◽  
A. Abed Abud ◽  
...  

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.


2010 ◽  
Vol 25 (27n28) ◽  
pp. 5097-5104
Author(s):  
◽  
KAZUHIRO YAMAMOTO

We present the latest results on searches for the standard and beyond-the-standard model Higgs bosons in proton-antiproton collisions at [Formula: see text] by the CDF and DØ experiments at the Fermilab Tevatron. No significant excess is observed above the expected background, and the cross section limits for the Higgs bosons are calculated. It is noticed that the standard model Higgs boson in the mass range 163 – 166 GeV/c2 is excluded at the 95% C.L.


1991 ◽  
Vol 06 (39) ◽  
pp. 3565-3572
Author(s):  
M. H. NOUS ◽  
M. El-KISHEN ◽  
A. M. ALGELANI

The production cross-sections for a triple gauge boson has been investigated in both the standard model and the minimal supersymmetric standard model, via e+e-→W+W-Z0. All events that contain the Higgs-boson seem to have no influence in this process. At [Formula: see text], this process could be detected with a reasonable cross-section, the production mechanism in this case will be e+e-→Z0→W+W-→W+W-Z0.


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

Abstract Measurements of the fiducial inclusive and differential production cross sections of the Higgs boson in proton-proton collisions at $$ \sqrt{s} $$ s = 13 TeV are performed using events where the Higgs boson decays into a pair of W bosons that subsequently decay into a final state with an electron, a muon, and a pair of neutrinos. The analysis is based on data collected with the CMS detector at the LHC during 2016–2018, corresponding to an integrated luminosity of 137 fb−1. Production cross sections are measured as a function of the transverse momentum of the Higgs boson and the associated jet multiplicity. The Higgs boson signal is extracted and simultaneously unfolded to correct for selection efficiency and resolution effects using maximum-likelihood fits to the observed distributions in data. The integrated fiducial cross section is measured to be 86.5 ± 9.5 fb, consistent with the Standard Model expectation of 82.5 ± 4.2 fb. No significant deviation from the Standard Model expectations is observed in the differential measurements.


1996 ◽  
Vol 11 (09) ◽  
pp. 1541-1550 ◽  
Author(s):  
TAO HAN

We discuss the Standard-Model Higgs boson production in the channels e−e−→e−e−H, e−νW−H, and e−e−ZH. We also illustrate the enhancements in the W–W– cross section that would result from a strongly-interacting Higgs sector or from a H−− resonance in a doublet + triplet scalar field model.


2001 ◽  
Vol 16 (supp01a) ◽  
pp. 308-310 ◽  
Author(s):  
J. Goldstein ◽  
C. S. Hill ◽  
J. Incandela ◽  
Stephen Parke ◽  
D. Rainwater ◽  
...  

The production of a Standard Model Higgs boson in association with a top quark pair at the upcoming high luminosity run (15 fb -1 integreted luminosity) of the Fermilab Tevatron [Formula: see text] is revisited. For Higgs masses below 140 GeV we demonstrate that the production cross section times branching ratio for [Formula: see text] decays yields a significant number of events and that this mode is competitive with and complementary to the searches using [Formula: see text], ZH associated production. For higher mass Higgs bosons the H → W+ W- decays are more difficult but have the potential to provide a few spectacular events.


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 ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document