Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userIdentifying the nature of dark matter at $e^{-}e^{+}$ Colliders
89
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
In this work, we consider the process $e^{+}+e^{-}rightarrow bbar{b}+slashed{E}_{T}$, at the future electron-positron colliders such as the International Linear Collider and Compact Linear Collider, to look for the dark matter (DM) effect and identify its nature at two different center-of-mass energies $E_{c.m.}=500~mathrm{GeV}~and~1~mathrm{TeV}$. For this purpose, we take two extensions of the standard model, in which the DM could be a real scalar or a heavy right-handed neutrino (RHN) similar to many models motivated by neutrino mass. In the latter extension, the charged leptons are coupled to the RHNs via a lepton flavor violating interaction that involves a charged singlet scalar. After discussing different constraints, we define a set of kinematical cuts that suppress the background, and generate different distributions that are useful in identifying the DM nature. The use of polarized beams (like the polarization $P(e^{-},e^{+})=left[+0.8,-0.3right]$ at the International Linear Collider) makes the signal detection easier and the DM identification more clear, where the statistical significance gets enhanced by twice (five times) for scalar (RHN) DM.
rate research
Read More
As any e$^+$e$^-$ scattering process can be accompanied by a hard photon emission from the initial state radiation, the analysis of the energy spectrum and angular distributions of those photons can be used to search for hard processes with an invisible final state. Thus high energy e$^+$e$^-$ colliders offer a unique possibility for the most general search of Dark matter based on the mono-photon signature. We consider production of DM particles via a mediator at the International Linear Collider (ILC) and Compact Linear Collider (CLIC) experiments taking into account detector effects within the DELPHES fast simulation framework. Limits on the light DM production in a generic model are set for a wide range of mediator masses and widths. For mediator masses up to the centre-of-mass energy of the collider, results from the mono-photon analysis are more stringent than the limits expected from direct resonance searches in Standard Model decay channels.
Information deformation and loss in jet clustering are one of the major limitations for precisely measuring hadronic events at future $e^-e^+$ colliders. Because of their dominance in data, the measurements of such events are crucial for advancing the precision frontier of Higgs and electroweak physics in the next decades. We show that this difficulty can be well-addressed by synergizing the event-level information into the data analysis, with the techniques of deep neutral network. In relation to this, we introduce a CMB-like observable scheme, where the event-level kinematics is encoded as Fox-Wolfram (FW) moments at leading order and multi-spectra at higher orders. Then we develop a series of jet-level (w/ and w/o the FW moments) and event-level classifiers, and analyze their sensitivity performance comparatively with two-jet and four-jet events. As an application, we analyze measuring Higgs decay width at $e^-e^+$ colliders with the data of 5ab$^{-1}@$240GeV. The precision obtained is significantly better than the baseline ones presented in documents. We expect this strategy to be applied to many other hadronic-event measurements at future $e^-e^+$ colliders, and to open a new angle for evaluating their physics capability.
Motivated by the ATLAS and CMS announcements of the excesses of di-photon events, we discuss the production and decay processes of di-photon resonance at future $e^+e^-$ colliders. We assume that the excess of the di-photon events at the LHC is explained by a scalar resonance decaying into a pair of photons. In such a case, the scalar interacts with standard model gauge bosons and, consequently, the production of such a scalar is possible at the $e^+e^-$ colliders. We study the production of the scalar resonance via the associated production with photon or $Z$, as well as via the vector-boson fusion, and calculate the cross sections of these processes. We also study the backgrounds, and discuss the detectability of the signals of scalar production with various decay processes of the scalar resonance. We also consider the case where the scalar resonance has an invisible decay mode, and study how the invisible decay can be observed at the $e^+e^-$ colliders.
A short review of the history and a slide-show of QCD tests in $e^+e^-$ annihilation is given. The world summary of measurements of $alpha_s$ is updated.
In gauge-Higgs unification the 4D Higgs boson appears as a part of the fifth dimensional component of gauge potentials, namely as a fluctuation mode of the Aharonov-Bohm phase in the extra dimension. The $SO(5) times U(1) times SU(3)$ gauge-Higgs unification gives nearly the same phenomenology as the standard model (SM) at low energies. It predicts KK excited states of photon, $Z $ boson, and $Z_R$ boson ($Z$ bosons) around 7 - 8 TeV. Quarks and leptons couple to these $Z$ bosons with large parity violation, which leads to distinct interference effects in $e^+ e^- rightarrow mu^+ mu^-, q , bar q$ processes. At 250 GeV ILC with polarized electron beams, deviation from SM can be seen at the 3 - 5 sigma level even with 250 fb$^{-1}$ data, namely in the early stage of ILC. Signals become stronger at higher energies. Precision measurements of interference effects at electron-positron colliders at energies above 250 GeV become very important to explore physics beyond the standard model.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
