No Arabic abstract
The resonance production of new chiral spin-1 bosons and their detection through the Drell--Yan process at the CERN LHC is considered. Quantitative evaluations of various differential cross-sections of the chiral bosons production are made within the CalcHEP package. The new neutral chiral bosons can be observed as a Breit--Wigner resonance peak in the invariant dilepton mass distribution, as usual. However, unique new signatures of the chiral bosons exist. First, there is no Jacobian peak in the lepton transverse momentum distribution. Second, the lepton angular distribution in the Collins-Soper frame for the high on-peak invariant masses of the lepton pairs has a peculiar swallowtail shape.
FASER is a proposed small and inexpensive experiment designed to search for light, weakly-interacting particles during Run 3 of the LHC from 2021-23. Such particles may be produced in large numbers along the beam collision axis, travel for hundreds of meters without interacting, and then decay to standard model particles. To search for such events, FASER will be located 480 m downstream of the ATLAS IP in the unused service tunnel TI12 and be sensitive to particles that decay in a cylindrical volume with radius R=10 cm and length L=1.5 m. FASER will complement the LHCs existing physics program, extending its discovery potential to a host of new, light particles, with potentially far-reaching implications for particle physics and cosmology. This document describes the technical details of the FASER detector components: the magnets, the tracker, the scintillator system, and the calorimeter, as well as the trigger and readout system. The preparatory work that is needed to install and operate the detector, including civil engineering, transport, and integration with various services is also presented. The information presented includes preliminary cost estimates for the detector components and the infrastructure work, as well as a timeline for the design, construction, and installation of the experiment.
In a composite model of the weak bosons the p-wave bosons are studied. The state with the lowest mass is identified with the boson, which has been observed at the LHC. Specific properties of the excited bosons are studied, in particular their decays into weak bosons and photons. Such decays might have been observed recently with the ATLAS detector at the Large Hadron Collider.
The search for heavy Higgs bosons is an essential step in the exploration of the Higgs sector and in probing the Supersymmetric parameter space. This paper discusses the constraints on the M(A) and tan beta parameters derived from the bounds on the different decay channels of the neutral H and A bosons accessible at the LHC, in the framework of the phenomenological MSSM. The implications from the present LHC results and the expected sensitivity of the 14 TeV data are discussed in terms of the coverage of the [M(A) - tan beta] plane. New channels becoming important at 13 and 14 TeV for low values of tan beta are characterised in terms of their kinematics and the reconstruction strategies. The effect of QCD systematics, SUSY loop effects and decays into pairs of SUSY particles on these constraints are discussed in details.
It is widely considered that, for Higgs boson searches at the Large Hadron Collider, WH and ZH production where the Higgs boson decays to b anti-b are poor search channels due to large backgrounds. We show that at high transverse momenta, employing state-of-the-art jet reconstruction and decomposition techniques, these processes can be recovered as promising search channels for the standard model Higgs boson around 120 GeV in mass.
The next-to-minimal supersymmetric standard model (NMSSM) with an extended Higgs sector offers one of the Higgs boson as the Standard model (SM) like Higgs with a mass around 125 GeV along with other Higgs bosons with lighter and heavier masses and not excluded by any current experiments. At the LHC, phenomenology of these non SM like Higgs bosons is very rich and considerably different from the other supersymmetric models. In this work, assuming one of the Higgs bosons to be the SM like, we revisit the mass spectrum and couplings of non SM like Higgs bosons taking into consideration all existing constraints and identify the relevant region of parameter space. The discovery potential of these non SM like Higgs bosons, apart from their masses, is guided by their couplings with gauge bosons and fermions which are very much parameter space sensitive. We evaluate the rates of productions of these non SM like Higgs bosons at the LHC for a variety of decay channels in the allowed region of the parameter space. Although bb, {tau}{tau} decay modes appear to be the most promising, it is observed that for a substantial region of parameter space the two-photon decay mode has a remarkably large rate. In this work we emphasize that this diphoton mode can be exploited to find the NMSSM Higgs signal and can also be potential avenue to distinguish the NMSSM from the MSSM. In addition, we discuss briefly the various detectable signals of these non SM Higgs bosons at the LHC.