1,048 research outputs found
Background Monte Carlo Samples for a Future Hadron Collider
A description of Standard Model background Monte Carlo samples produced for
studies related to future hadron colliders
Measurement of the Z/gamma* + b-jet cross section in pp collisions at 7 TeV
The production of b jets in association with a Z/gamma* boson is studied
using proton-proton collisions delivered by the LHC at a centre-of-mass energy
of 7 TeV and recorded by the CMS detector. The inclusive cross section for
Z/gamma* + b-jet production is measured in a sample corresponding to an
integrated luminosity of 2.2 inverse femtobarns. The Z/gamma* + b-jet cross
section with Z/gamma* to ll (where ll = ee or mu mu) for events with the
invariant mass 60 < M(ll) < 120 GeV, at least one b jet at the hadron level
with pT > 25 GeV and abs(eta) < 2.1, and a separation between the leptons and
the jets of Delta R > 0.5 is found to be 5.84 +/- 0.08 (stat.) +/- 0.72 (syst.)
+(0.25)/-(0.55) (theory) pb. The kinematic properties of the events are also
studied and found to be in agreement with the predictions made by the MadGraph
event generator with the parton shower and the hadronisation performed by
PYTHIA.Comment: Submitted to the Journal of High Energy Physic
Recent Progress and Next Steps for the MATHUSLA LLP Detector
We report on recent progress and next steps in the design of the proposed
MATHUSLA Long Lived Particle (LLP) detector for the HL-LHC as part of the
Snowmass 2021 process. Our understanding of backgrounds has greatly improved,
aided by detailed simulation studies, and significant R&D has been performed on
designing the scintillator detectors and understanding their performance. The
collaboration is on track to complete a Technical Design Report, and there are
many opportunities for interested new members to contribute towards the goal of
designing and constructing MATHUSLA in time for HL-LHC collisions, which would
increase the sensitivity to a large variety of highly motivated LLP signals by
orders of magnitude.Comment: Contribution to Snowmass 2021 (EF09, EF10, IF6, IF9), 18 pages, 12
figures. v2: included additional endorser
Report of the Topical Group on Electroweak Precision Physics and Constraining New Physics for Snowmass 2021
The precise measurement of physics observables and the test of their
consistency within the standard model (SM) are an invaluable approach,
complemented by direct searches for new particles, to determine the existence
of physics beyond the standard model (BSM). Studies of massive electroweak
gauge bosons (W and Z bosons) are a promising target for indirect BSM searches,
since the interactions of photons and gluons are strongly constrained by the
unbroken gauge symmetries. They can be divided into two categories: (a) Fermion
scattering processes mediated by s- or t-channel W/Z bosons, also known as
electroweak precision measurements; and (b) multi-boson processes, which
include production of two or more vector bosons in fermion-antifermion
annihilation, as well as vector boson scattering (VBS) processes. The latter
categories can test modifications of gauge-boson self-interactions, and the
sensitivity is typically improved with increased collision energy.
This report evaluates the achievable precision of a range of future
experiments, which depend on the statistics of the collected data sample, the
experimental and theoretical systematic uncertainties, and their correlations.
In addition it presents a combined interpretation of these results, together
with similar studies in the Higgs and top sector, in the Standard Model
effective field theory (SMEFT) framework. This framework provides a
model-independent prescription to put generic constraints on new physics and to
study and combine large sets of experimental observables, assuming that the new
physics scales are significantly higher than the EW scale.Comment: 55 pages; Report of the EF04 topical group for Snowmass 202
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