764 research outputs found
Top Quark Pairs at High Invariant Mass - A Model-Independent Discriminator of New Physics at the LHC
We study top quark pair production to probe new physics at the LHC. We
propose reconstruction methods for semileptonic events and use them
to reconstruct the invariant mass. The angular distribution of top
quarks in their c.m. frame can determine the spin and production subprocess for
each new physics resonance. Forward-backward asymmetry and CP-odd variables can
be constructed to further delineate the nature of new physics. We parametrize
the new resonances with a few generic parameters and show high invariant mass
top pair production may provide an early indicator for new physics beyond the
Standard Model.Comment: 5 pages, 4 figures; version to appear in PR
Using a Primordial Gravitational Wave Background to Illuminate New Physics
A primordial spectrum of gravitational waves serves as a backlight to the
relativistic degrees of freedom of the cosmological fluid. Any change in the
particle physics content, due to a change of phase or freeze-out of a species,
will leave a characteristic imprint on an otherwise featureless primordial
spectrum of gravitational waves and indicate its early-Universe provenance. We
show that a gravitational wave detector such as the Laser Interferometer Space
Antenna would be sensitive to physics near 100 TeV in the presence of a
sufficiently strong primordial spectrum. Such a detection could complement
searches at newly proposed 100 km circumference accelerators such as the Future
Circular Collider at CERN and the Super Proton-Proton Collider in China,
thereby providing insight into a host of beyond Standard Model issues,
including the hierarchy problem, dark matter, and baryogenesis.Comment: 7 pages, 3 figures; added reference
Single Top Production as a Probe of B-prime Quarks
We show how single top production at the LHC can be used to discover (and
characterize the couplings of) B' quarks, which are an essential part of many
natural models of new physics beyond the Standard Model. We present the B'
effective model and concentrate on resonant production via a colored anomalous
magnetic moment. Generally, B's preferentially decay into a single top quark
produced in association with a W boson; thus, this production process makes
associated single top production essential to B' searches at the LHC. We
demonstrate the background processes are manageable and the signal cross
section is sufficient to yield a large signal significance even during the 7
TeV LHC run. Specifically, we show that B' masses of 700 GeV or more can be
probed. Moreover, if a B' is found, then the chirality of its coupling can be
determined. Finally, we present signal cross sections for several different LHC
energies.Comment: 19 pages, 7 figures, 1 tabl
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