scholarly journals Precision inclusive Higgs physics at e+e− colliders with tracking detectors and without calorimetry

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Patrick Draper ◽  
Jonathan Kozaczuk ◽  
Scott Thomas

Abstract A primary goal of a future e+e− collider program will be the precision measurement of Higgs boson properties. For practical reasons it is of interest to determine the minimal set of detector specifications required to reach this and other scientific goals. Here we investigate the precision obtainable for the e+e−Zhμ+μ−X inclusive cross section and the Higgs boson mass using the di-muon recoil method, considering a detector that has only an inner tracking system within a solenoidal magnetic field, surrounded by many nuclear interaction lengths of absorbing material, and an outer muon identification system. We find that the sensitivity achievable in these measurements with such a tracking detector is only marginally reduced compared to that expected for a general purpose detector with additional electromagnetic and hadronic calorimeter systems. The difference results mainly from multi-photon backgrounds that are not as easily rejected with tracking detectors. We also comment on the prospects for an analogous measurement of the e+e−→Zh→e+e−X inclusive cross section. Finally, we study searches for light scalars utilizing the di-muon recoil method, estimating the projected reach with a tracking or general purpose detector.

2016 ◽  
Vol 94 (11) ◽  
Author(s):  
J. Yan ◽  
S. Watanuki ◽  
K. Fujii ◽  
A. Ishikawa ◽  
D. Jeans ◽  
...  

2012 ◽  
Vol 27 (28) ◽  
pp. 1250165 ◽  
Author(s):  
M. HASHEMI

The charged Higgs production associated with a W± boson has a smooth cross-section as a function of the charged Higgs mass at muon colliders. The cross-section in minimal supersymmetric standard model (MSSM) is about 25 fb in the range 200 GeV < mH± <400 GeV with tan β = 50. This is much larger than the corresponding cross-section at an e+e- collider which reaches a fraction of femtobarn. The observability of this charged Higgs production at a muon collider has been recently studied in an earlier work leading to the result that with 1 ab-1, a 5σ signal can be observed throughout the aforementioned mass range. In this paper, results of a study based on a general two Higgs doublet model (types II and III) are presented and the cross-section of the charged Higgs production in the most sensitive parameter space is evaluated. It is concluded that the cross-section increases with increasing neutral Higgs boson masses involved in the s-channel diagram and can be as large as several picobarn with tan β = 50. The region of "physical Higgs boson mass" parameter space which could lead to a 5σ signal at 50 fb-1 is specified.


2014 ◽  
Vol 29 (10) ◽  
pp. 1430009
Author(s):  
Kyle J. Knoepfel

We give an overview of Standard Model (SM) Higgs boson studies performed at the CDF and D∅ experiments at the Tevatron proton–antiproton collider. Combining the results of many individual analyses, most of which use the full data set available, an excess with a significance of 3.0 standard deviations with respect to the SM hypothesis is observed at a Higgs boson mass of 125 GeV /c2. At that mass, the combined best-fit cross-section is consistent with the SM prediction. Constraints are also placed on the Higgs boson couplings with fermions and electroweak vector bosons and are consistent with the SM predictions within the uncertainties.


2021 ◽  
Vol 137 (1) ◽  
Author(s):  
Paolo Azzurri ◽  
Gregorio Bernardi ◽  
Sylvie Braibant ◽  
David d’Enterria ◽  
Jan Eysermans ◽  
...  

AbstractThe FCC-ee offers powerful opportunities to determine the Higgs boson parameters, exploiting over $$10^6$$ 10 6 $${ \hbox {e}^+\hbox {e}^- \rightarrow \hbox {ZH}}$$ e + e - → ZH events and almost $$10^5$$ 10 5 $${ \hbox {WW} \rightarrow \hbox {H}}$$ WW → H events at centre-of-mass energies around 240 and 365 GeV. This essay spotlights the important measurements of the ZH production cross section and of the Higgs boson mass. The measurement of the total ZH cross section is an essential input to the absolute determination of the HZZ coupling—a “standard candle” that can be used by all other measurements, including those made at hadron colliders—at the per-mil level. A combination of the measured cross sections at the two different centre-of-mass energies further provides the first evidence for the trilinear Higgs self-coupling, and possibly its first observation if the cross section measurement can be made accurate enough. The determination of the Higgs boson mass with a precision significantly better than the Higgs boson width (4.1 MeV in the standard model) is a prerequisite to either constrain or measure the electron Yukawa coupling via direct $${ \hbox {e}^+\hbox {e}^- \rightarrow \hbox {H}}$$ e + e - → H production at $$\sqrt{s} = 125$$ s = 125  GeV. Approaching the statistical limit of 0.1% and $${\mathcal {O}}(1)$$ O ( 1 )  MeV on the ZH cross section and the Higgs boson mass, respectively, sets highly demanding requirements on accelerator operation (ZH threshold scan, centre-of-mass energy measurement), detector design (lepton momentum resolution, hadronic final state reconstruction performance), theoretical calculations, and analysis techniques (efficiency and purity optimization with modern tools, constrained kinematic fits, control of systematic uncertainties). These challenges are examined in turn in this essay


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.


2001 ◽  
Vol 501 (1-2) ◽  
pp. 69-77 ◽  
Author(s):  
A. Katsikatsou ◽  
A.B. Lahanas ◽  
D.V. Nanopoulos ◽  
V.C. Spanos

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