The instrumentation of the very forward region of a detector at a future linear collider (ILC, CLIC) is briefly reviewed. The status of the FCAL R&D activity is given with emphasis on physics and ...technological challenges. The current status of studies on absolute luminosity measurement, luminosity spectrum reconstruction and high-energy electron identification with the forward calorimeters is given. The impact of FCAL measurements on physics studies is illustrated with an example of the σHWW⋅BR(H→μ+μ−) measurement at 1.4 TeV CLIC.
The Compact Linear Collider (CLIC) is an option for a future
e
+
e
-
collider operating at centre-of-mass energies up to
3
TeV
, providing sensitivity to a wide range of new physics phenomena and ...precision physics measurements at the energy frontier. This paper is the first comprehensive presentation of the Higgs physics reach of CLIC operating at three energy stages:
s
=
350
GeV
, 1.4 and
3
TeV
. The initial stage of operation allows the study of Higgs boson production in Higgsstrahlung (
e
+
e
-
→
Z
H
) and
W
W
-fusion (
e
+
e
-
→
H
ν
e
ν
¯
e
), resulting in precise measurements of the production cross sections, the Higgs total decay width
Γ
H
, and model-independent determinations of the Higgs couplings. Operation at
s
>
1
TeV
provides high-statistics samples of Higgs bosons produced through
W
W
-fusion, enabling tight constraints on the Higgs boson couplings. Studies of the rarer processes
e
+
e
-
→
t
t
¯
H
and
e
+
e
-
→
H
H
ν
e
ν
¯
e
allow measurements of the top Yukawa coupling and the Higgs boson self-coupling. This paper presents detailed studies of the precision achievable with Higgs measurements at CLIC and describes the interpretation of these measurements in a global fit.
A
bstract
The Compact Linear Collider (CLIC) is a proposed future high-luminosity linear electron-positron collider operating at three energy stages, with nominal centre-of-mass energies
s
= 380 GeV, ...1
.
5 TeV, and 3 TeV. Its aim is to explore the energy frontier, providing sensitivity to physics beyond the Standard Model (BSM) and precision measurements of Standard Model processes with an emphasis on Higgs boson and top-quark physics. The opportunities for top-quark physics at CLIC are discussed in this paper. The initial stage of operation focuses on top-quark pair production measurements, as well as the search for rare flavour-changing neutral current (FCNC) top-quark decays. It also includes a top-quark pair production threshold scan around 350 GeV which provides a precise measurement of the top-quark mass in a well-defined theoretical framework. At the higher-energy stages, studies are made of top-quark pairs produced in association with other particles. A study of t
̄
tH production including the extraction of the top Yukawa coupling is presented as well as a study of vector boson fusion (VBF) production, which gives direct access to high-energy electroweak interactions. Operation above 1 TeV leads to more highly collimated jet environments where dedicated methods are used to analyse the jet constituents. These techniques enable studies of the top-quark pair production, and hence the sensitivity to BSM physics, to be extended to higher energies. This paper also includes phenomenological interpretations that may be performed using the results from the extensive top-quark physics programme at CLIC.
CPV in H at 1 TeV ILC Vukašinović, N.; Agatonović-Jovin, T.; Božović-Jelisavc̆ić, I. ...
Moscow University physics bulletin,
2022/4, Letnik:
77, Številka:
2
Journal Article
Recenzirano
CP violation is one of Sakharov’s conditions for the matter-antimatter asymmetry of the Universe. The experimentally observed size of CP violation is insufficient to account for this. Is CP violated ...in the Higgs sector? Could the SM-like Higgs boson be a mixture of CP even and CP odd states of an extended Higgs sector? With what precision could such effects be measured at future electron-positron colliders? These questions will be discussed in the light of the latest studies at ILC.
Although the studies of tensor structure of the Higgs boson interactions with vector bosons and fermions at CMS and ATLAS experiments have established that the \(J^{\mathrm{PC}}\) quantum numbers of ...the Higgs boson should be \(0^{++}\), small CP violation in the Higgs sector (up to 10% contribution of the CP-odd state) cannot be excluded with the current experimental precision. We review possibilities to measure CP violating mixing angle \(\Psi_{\mathrm{CP}}\) between scalar and pseudoscalar states, at a linear electron-positron collider, at center-of-mass energy of 1 TeV.
With the current precision of measurements by the ATLAS and CMS experiments,
it cannot be excluded that a SM-like Higgs boson is a CP violating mixture of
CP-even and CP-odd states. We explore this ...possibility here, assuming Higgs
boson production in ZZ-fusion, at 1 TeV ILC, with unpolarized beams. The full
simulation of SM background and fast simulation of the signal is performed,
simulating 8 ab$^{-1}$ of data collected with the ILD detector. We demonstrate
that the CP mixing angle $\Psi_{\mathrm{CP}}$ between scalar and pseudoscalar
states can be measured with the statistical uncertainty of 3.8 mrad at 68% CL,
corresponding to 1.44 $\cdot 10^{-5}$ for the CP parameter $f_\mathrm{CP}$, for
the pure scalar state. This is the first result on sensitivity of an
$e^{+}e^{-}$ collider to measure $f_\mathrm{CP}$ in the Higgs production vertex
in vector boson fusion.
In this paper we investigate the prospects for measuring the branching fraction of the Standard Model Higgs boson decay into a pair of \(Z\) bosons at the future Compact Linear Collider (CLIC) at 350 ...GeV and 3 TeV centre-of-mass energies. Studies are performed using a detailed simulation of the detector for CLIC, taking into consideration all relevant physics and beam-induced background processes. It is shown that the product of the Higgs production cross-section and the branching fraction BR(\({H\rightarrow\thinspace ZZ^\ast}\)) can be measured with a relative statistical uncertainty of 20% (3.0%) at a centre-of-mass energy of 350 GeV (3 TeV) using semileptonic final states, assuming an integrated luminosity of 1 ab\(^{-1}\) (5 ab\(^{-1}\)).
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