scholarly journals Higgs production in association with a dark-Z at future electron positron colliders

2021 ◽  
Author(s):  
Pierce Giffin ◽  
Ian M. Lewis ◽  
Yajuan Zheng
Keyword(s):  
Higgs Physics ◽  
Higgs Boson ◽  
Gauge Boson ◽  
Energy Resolution ◽  
Cross Sections ◽  
Linear Collider ◽  
International Linear Collider ◽  
Precision Measurements ◽  
Dark Photon ◽  
Electron Positron

Abstract In recent years there have been many proposals for new electron-positron colliders, such as the Circular Electron-Positron Collider, the International Linear Collider, and the Future Circular Collider in electron-positron mode. Much of the motivation for these colliders is precision measurements of the Higgs boson and searches for new electroweak states. Hence, many of these studies are focused on energies above the h Z threshold. However, there are proposals to run these colliders at the lower WW threshold and Z-pole energies. In this paper, we study a new search for Higgs physics accessible at lower energies: e+e− → h Zd, where Zdis a new light gauge boson such as a dark photon or dark-Z. Such searches can be conducted at the WW threshold, i.e. energies below the h Z threshold where exotic Higgs decays can be searched for in earnest. Additionally, due to very good angular and energy resolution at future electron-positron colliders, these searches will be sensitive to Zd masses below 1 GeV, which is lower than the current direct LHC searches. We will show that at √s = 160 GeV with 10 ab−1, a search for e+e− → h Zd is sensitive to h −Z −Zd couplings of δ ∼ 9 × 10−3and cross sections of ∼ 2 − 3 ab for Zd masses below 1 GeV. The results are similar at √s = 240 GeV with 5 ab−1.

scholarly journals Indirect reach of heavy MSSM Higgs bosons by precision measurements at future lepton colliders

2015 ◽  
Vol 30 (33) ◽  
pp. 1550192 ◽  
Author(s):  
Mitsuru Kakizaki ◽  
Shinya Kanemura ◽  
Mariko Kikuchi ◽  
Toshinori Matsui ◽  
Hiroshi Yokoya
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
W Boson ◽  
Linear Collider ◽  
Standard Model Prediction ◽  
Branching Fraction ◽  
International Linear Collider ◽  
Higgs Bosons ◽  
Boson Mass ◽  
Electron Positron

In the Minimal Supersymmetric Standard Model (MSSM), the bottom Yukawa coupling of the Higgs boson can considerably deviate from its Standard Model prediction due to nondecoupling effects. We point out that the ratio of the Higgs boson decay branching fraction to a bottom quark pair and that to a W-boson pair from the same production channel is particularly sensitive to large additional MSSM Higgs boson mass regions at future electron–positron colliders. Based on this precision measurement, we explicitly show the indirect discovery reach of the additional Higgs bosons according to planned programs of the International Linear Collider.

scholarly journals NLO QCD corrections to exclusive quarkonium-pair production in photon–photon collision

2020 ◽  
Vol 80 (9) ◽  
Author(s):  
Hao Yang ◽  
Zi-Qiang Chen ◽  
Cong-Feng Qiao
Keyword(s):  
Pair Production ◽  
Cross Sections ◽  
Linear Collider ◽  
International Linear Collider ◽  
Leading Order ◽  
Numerical Result ◽  
Electron Positron ◽  
Belle Ii ◽  
Exclusive Processes ◽  
Photon Collision

AbstractWe calculate the next-to-leading order (NLO) quantum chromodynamics (QCD) corrections to the exclusive processes $$\gamma +\gamma \rightarrow {\mathcal {Q}}+{\mathcal {Q}}$$ γ + γ → Q + Q , with $${\mathcal {Q}}=J/\psi ,\ \eta _c,\ \Upsilon $$ Q = J / ψ , η c , Υ , or $$\eta _b$$ η b , in the framework of non-relativistic QCD (NRQCD) factorization formalism. The cross sections at the SuperKEKB electron–positron collider, as well as at the future colliders, like the circular electron positron collider (CEPC) and the international linear collider (ILC), are evaluated. Numerical result indicates that the processes for $$J/\psi $$ J / ψ -pair production and $$\eta _c$$ η c -pair production are hopefully observable at the Belle II detector within the next decade.

scholarly journals Higgs boson production in the U(1)B−L model at the ILC

2016 ◽  
Vol 31 (17) ◽  
pp. 1650099 ◽  
Author(s):  
Jinzhong Han ◽  
Bingfang Yang ◽  
Ning Liu ◽  
Jitao Li
Keyword(s):  
Higgs Boson ◽  
Cross Sections ◽  
Linear Collider ◽  
Decay Channel ◽  
Production Cross ◽  
International Linear Collider ◽  
Boson Production ◽  
Higgs Boson Production ◽  
Higgs Decay ◽  
Production Processes

In the framework of the minimal [Formula: see text] extension of the Standard Model, we investigate the Higgs boson production processes [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] at the International Linear Collider (ILC). We present the production cross-sections, the relative corrections and compare our results with the expected experimental accuracies for Higgs decay channel [Formula: see text]. In the allowed parameter space, we find that the effects of the three single Higgs boson production processes might approach the observable threshold of the ILC. But the Higgs signal strengths [Formula: see text] of the two double Higgs boson production processes are all out of the observable threshold so that these effects will be difficult to be observed at the ILC.

Triple Higgs boson production at ILC in the Higgs triplet model

2014 ◽  
Vol 29 (23) ◽  
pp. 1450092 ◽  
Author(s):  
Jun Cao ◽  
Jie-Fen Shen
Keyword(s):  
Higgs Boson ◽  
Cross Sections ◽  
Linear Collider ◽  
Production Cross ◽  
International Linear Collider ◽  
Triplet Model ◽  
Large Production ◽  
Doubly Charged ◽  
Parameter Values ◽  
Higgs Triplet Model

Besides the Standard Model (SM)-like Higgs boson h, the Higgs Triplet Model (HTM) predicts the existence of charged and doubly charged Higgs bosons (H±and H±±). In this paper, we focus on the study of the triple Higgs production at the International Linear Collider (ILC): e-e+→hH+H-and e-e+→hH++H–. We present the production cross-sections and discuss the relevant SM backgrounds. Our numerical results show that, with reasonable parameter values, the values of the cross-sections for two processes can reach the level several fb and tens of fb, respectively. Due to large production cross-section and small SM background, the possible signals of H±and H±±might be detected via these processes in the future ILC experiments.

Preliminary conceptual design about the CEPC calorimeters

2016 ◽  
Vol 31 (33) ◽  
pp. 1644026 ◽  
Author(s):  
Haijun Yang
Keyword(s):  
Conceptual Design ◽  
Linear Collider ◽  
International Linear Collider ◽  
Electromagnetic Calorimeter ◽  
Hadronic Jets ◽  
Baseline Design ◽  
Active Sensor ◽  
Electron Positron ◽  
Physics Potential ◽  
Conceptual Design Report

The Circular Electron Positron Collider (CEPC) as a Higgs factory was proposed in September 2013. The preliminary conceptual design report was completed in 2015.1 The CEPC detector design was using International Linear Collider Detector — ILD2 as an initial baseline. The CEPC calorimeters, including the high granularity electromagnetic calorimeter (ECAL) and the hadron calorimeter (HCAL), are designed for precise energy measurements of electrons, photons, taus and hadronic jets. The basic resolution requirements for the ECAL and HCAL are about 16%[Formula: see text][Formula: see text] (GeV) and 50%[Formula: see text][Formula: see text] (GeV), respectively. To fully exploit the physics potential of the Higgs, [Formula: see text], [Formula: see text] and related Standard Model processes, the jet energy resolution is required to reach 3%–4%, or 30%/[Formula: see text] (GeV) at energies below about 100 GeV. To achieve the required performance, a Particle Flow Algorithm (PFA) — oriented calorimetry system is being considered as the baseline design. The CEPC ECAL detector options include silicon–tungsten or scintillator–tungsten structures with analog readout, while the HCAL detector options have scintillator or gaseous detector as the active sensor and iron as the absorber. Some latest R&D studies about ECAL and HCAL within the CEPC working group is also presented.

Searching for the doubly charged scalars in the Georgi–Machacek model via γγ collisions at the ILC

2018 ◽  
Vol 33 (11) ◽  
pp. 1841003
Author(s):  
Jun Cao ◽  
Yu-Qi Li ◽  
Yao-Bei Liu
Keyword(s):  
Cross Sections ◽  
Linear Collider ◽  
Coupling Parameter ◽  
Production Cross ◽  
International Linear Collider ◽  
Scalar Coupling ◽  
Decay Channels ◽  
Decay Modes ◽  
The Future ◽  
Doubly Charged

The Georgi–Machacek (GM) model predicts the existence of the doubly-charged scalars [Formula: see text], which can be seen the typical particles in this model and their diboson decay channels are one of the most promising ways to discover such new doubly-charged scalars. Based on the constraints of the latest combined ATLAS and CMS Higgs boson diphoton signal strength data at [Formula: see text] confidence level, we focus on the study of the triple scalar production in [Formula: see text] collisions at the future International Linear collider (ILC): [Formula: see text], where the production cross-sections are very sensitive to the triple scalar coupling parameter [Formula: see text]. Considering the typical same-sign diboson decay modes for the doubly-charged scalars, the possible final signals might be detected via this process at the future ILC experiments.

scholarly journals Double Higgs boson production and Higgs self-coupling extraction at CLIC

2020 ◽  
Vol 80 (11) ◽  
Author(s):  
Philipp Roloff ◽  
Ulrike Schnoor ◽  
Rosa Simoniello ◽  
Boruo Xu
Keyword(s):  
Higgs Boson ◽  
Cross Section ◽  
W Boson ◽  
Linear Collider ◽  
Invariant Mass Distribution ◽  
Gauge Coupling ◽  
High Energy ◽  
Electron Positron ◽  
The Cross ◽  
Detector Simulation

AbstractThe Compact Linear Collider (CLIC) is a future electron–positron collider that will allow measurements of the trilinear Higgs self-coupling in double Higgs boson events produced at its high-energy stages with collision energies from $$\sqrt{s}$$ s  = 1.4 to 3 TeV. The sensitivity to the Higgs self-coupling is driven by the measurements of the cross section and the invariant mass distribution of the Higgs-boson pair in the W-boson fusion process, $$\text {e}^{+}\text {e}^{-}\rightarrow {\text {H}\text {H}\nu \bar{\nu }}$$ e + e - → HH ν ν ¯ . It is enhanced by including the cross-section measurement of ZHH production at 1.4 TeV. The expected sensitivity of CLIC for Higgs pair production through W-boson fusion is studied for the decay channels $$\mathrm{b}\bar{\mathrm{b}}\mathrm{b}\bar{\mathrm{b}}$$ b b ¯ b b ¯   and $$\mathrm{b}\bar{\mathrm{b}}\mathrm{W}\mathrm{W}^{*}$$ b b ¯ W W ∗   using full detector simulation including all relevant backgrounds at $$\sqrt{s}$$ s = 1.4 TeV with an integrated luminosity of $$\mathcal {L}$$ L  = 2.5 ab$$^{-1}$$ - 1 and at $$\sqrt{s}$$ s = 3 TeV with $$\mathcal {L}$$ L  = 5 ab$$^{-1}$$ - 1 . Combining $$\text {e}^{+}\text {e}^{-}\rightarrow {\text {H}\text {H}\nu \bar{\nu }}$$ e + e - → HH ν ν ¯ and ZHH  cross-section measurements at 1.4 TeV with differential measurements in $$\text {e}^{+}\text {e}^{-}\rightarrow {\text {H}\text {H}\nu \bar{\nu }}$$ e + e - → HH ν ν ¯ events at 3 TeV, CLIC will be able to measure the trilinear Higgs self-coupling with a relative uncertainty of $$-8\%$$ - 8 % and $$ +11\%$$ + 11 % at 68% C.L., assuming the Standard Model. In addition, prospects for simultaneous constraints on the trilinear Higgs self-coupling and the Higgs-gauge coupling HHWW are derived based on the $${\text {H}\text {H}\nu \bar{\nu }}$$ HH ν ν ¯ measurement.

scholarly journals The measurement of the $$H\rightarrow \tau \tau $$ signal strength in the future $$e^{+}e^{-}$$ Higgs factories

2020 ◽  
Vol 80 (1) ◽  
Author(s):  
Dan Yu ◽  
Manqi Ruan ◽  
Vincent Boudry ◽  
Henri Videau ◽  
Jean-Claude Brient ◽  
...  
Keyword(s):  
Linear Collider ◽  
Simulation Analysis ◽  
Center Of Mass ◽  
International Linear Collider ◽  
Signal Strength ◽  
Relative Accuracy ◽  
Hadronic Decay ◽  
Beam Polarization ◽  
Baseline Design ◽  
Electron Positron

AbstractThe Circular Electron Positron Collider and the International Linear Collider are two electron-positron Higgs factories. They are designed to operate at a center-of-mass energy of 240 and 250 GeV and accumulate 5.6 and 2 $$ab^{-1}$$ab-1 of integrated luminosity. This paper estimates their performance on the $$H \rightarrow \tau ^{+}\tau ^{-}$$H→τ+τ- benchmark measurement. Using the full simulation analysis, the CEPC is expected to measure the signal strength to a relative accuracy of 0.8%. Extrapolating to the ILC setup, we conclude the ILC can reach a relative accuracy of 1.1% or 1.2%, corresponding to two benchmark beam polarization setups. The physics requirement on the mass resolution of the Higgs boson with hadronic decay final states is also discussed, showing that the CEPC baseline design and reconstruction fulfill the accuracy requirement of the $$H\rightarrow \tau ^{+}\tau ^{-}$$H→τ+τ- signal strength.

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