6,047 research outputs found
Squark Pair Production in the MSSM with Explicit CP Violation
We analyze effects of the CP-odd soft phases in the MSSM on the
pair-productions of colored superpartners in pp collisions at the LHC energies.
We find that, among all pair-production processes, those of the scalar quarks
in the first and second generations are particularly sensitive to the CP-odd
phases, more precisely, to the phases of the gluinos and neutralinos. We
compute pair-production cross sections, classify various production modes
according to their dependencies on the gluino and neutralino phases, perform a
detailed numerical analysis to determine individual as well as total cross
sections, and give a detailed discussion of EDM bounds. We find that
pair-productions of first and second generation squarks serve as a viable probe
of the CP violation sources in the gaugino sector of the theory even if
experiments cannot determine chirality, flavor and electric charge of the
squarks produced.Comment: 36 pp, 14 ps figures, 1 table, Corrected the cross sections; mild
changes in numerical results; conclusion unchange
Higgs Boson Masses Of The MSSM With General Soft Breaking
The operators that break supersymmetry can be holomorphic or non-holomorphic
in structure. The latter do not pose any problem for gauge hierarchy and are
soft provided that the particle spectrum does not contain any gauge singlets.
In minimal supersymmetric model (MSSM) we discuss the impact of non-holomorphic
soft-breaking terms on the Higgs sector. We find that non-holomorphic operators
can cause significant changes as are best exhibited by the correlation between
the masses of the charginos and Higgs bosons.Comment: 9 pages, 2 figures; added new reference
Electroweak Stability and Discovery Luminosities for New Physics
What is the luminosity needed for discovering new physics if the electroweak
scale is to remain stable? In this work we study this question, with the
example of a real singlet scalar which couples to the Higgs field already at
the renormalizable level. Observing that the electroweak scale remains stable
if the two scalars couple in a seesawic fashion, we show that the HL-LHC,
expected to deliver an integrated luminosity around 3/ab, can discover scalars
weighing up to 800 GeV. The FCC-hh, on the other hand, can discover scalars as
heavy as 2.3 TeV at 100/ab luminosity. It thus follows that the new physics
that does not destabilize the electroweak scale can be accessed only at high
luminosities, and is not possible exclude by the current LHC results.Comment: 14 pages, 14 figures, 5 tables; journal versio
CMS HCAL Installation and Commissioning
The installation and commissioning of the Hadron Calorimeter system of the CMS detector is described and the performance of the various monitoring systems, the progress in the calibration work and the current plans for the HCAL calorimeter are summarized
Radiation-Hardness Measurements of High Content Quartz Fibres Irradiated with 24 GeV Protons up to 1.25 Grad
We investigated the darkening of two high OH- content quartz fibres irradiated with 24 GeV protons at the Cern PS facility IRRAD. The two tested fibres have a 0.6 mm quartz core diameter, one with hard plastic cladding (qp) and the other with quartz cladding (qq). These fibres were exposed at about 1.25 Gigarad in 3 weeks. The fibres became opaque below 380nm, and in the range 580-650 nm. The darkening under irradiation and damage recovery after irradiation as a function of dose and time are similar to what we observed with electrons. The typical attenuation at 455 nm are 1.44 + - 0.22 and 2.20 + - 0.15 dB/m at 100 Mrad for qp and qq fibres, respectively. The maximum damage recovery is also observed near this wavelength
The effect of supersymmetric CP phases on Chargino-Pair Production via Drell-Yan Process at the LHC
We compute the rates for pp annihilation into chargino-pairs via Drell-Yan
process taking into account the effects of supersymmetric soft phases, at
proton-proton collider. In particular, the phase of the mu parameter gains
direct accessibility via the production of dissimilar charginos. The phases of
the trilinear soft masses do not have a significant effect on the cross
sections.Comment: 24 pages, 7 figure
Quartz Plate Calorimeter as SLHC Upgrade to CMS Hadronic EndCap Calorimeters
Due to an expected increase in radiation damage under super-LHC conditions, we propose to substitute the scintillator tiles in the original design of the hadronic endcap (HE) calorimeter with quartz plates. Quartz is proved to be radiation hard by the radiation damage tests with electron, proton, neutron and gamma beams. Using wavelength shifting fibers, it is possible to collect efficiently the Cherenkov light generated in quartz plates. This paper summarizes the results from various test beams, bench tests, and Geant4 simulations done on methods of collecting light from quartz plates, as well as radiation hardness tests on quartz material
Search for a New Heavy Gauge Boson Wprime with Electron + missing ET Event Signature in ppbar collisions at sqrt(s)=1.96 TeV
We present a search for a new heavy charged vector boson decaying
to an electron-neutrino pair in collisions at a center-of-mass
energy of 1.96\unit{TeV}. The data were collected with the CDF II detector
and correspond to an integrated luminosity of 5.3\unit{fb}^{-1}. No
significant excess above the standard model expectation is observed and we set
upper limits on . Assuming standard
model couplings to fermions and the neutrino from the boson decay to
be light, we exclude a boson with mass less than
1.12\unit{TeV/}c^2 at the 95\unit{%} confidence level.Comment: 7 pages, 2 figures Submitted to PR
Measurement of the Forward-Backward Asymmetry in the B -> K(*) mu+ mu- Decay and First Observation of the Bs -> phi mu+ mu- Decay
We reconstruct the rare decays , , and in a data sample
corresponding to collected in collisions at
by the CDF II detector at the Fermilab Tevatron
Collider. Using and decays we report the branching ratios. In addition, we report
the measurement of the differential branching ratio and the muon
forward-backward asymmetry in the and decay modes, and the
longitudinal polarization in the decay mode with respect to the squared
dimuon mass. These are consistent with the theoretical prediction from the
standard model, and most recent determinations from other experiments and of
comparable accuracy. We also report the first observation of the {\mathcal{B}}(B^0_s \to
\phi\mu^+\mu^-) = [1.44 \pm 0.33 \pm 0.46] \times 10^{-6}27 \pm 6B^0_s$ decay observed.Comment: 7 pages, 2 figures, 3 tables. Submitted to Phys. Rev. Let
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