85 research outputs found
Physics at a 100 TeV pp collider: Higgs and EW symmetry breaking studies
This report summarises the physics opportunities for the study of Higgs
bosons and the dynamics of electroweak symmetry breaking at the 100 TeV pp
collider.Comment: 187 pages, 94 figures. Chapter 2 of the "Physics at the FCC-hh"
Repor
Jet Substructure at the Tevatron and LHC: New results, new tools, new benchmarks
In this report we review recent theoretical progress and the latest
experimental results in jet substructure from the Tevatron and the LHC. We
review the status of and outlook for calculation and simulation tools for
studying jet substructure. Following up on the report of the Boost 2010
workshop, we present a new set of benchmark comparisons of substructure
techniques, focusing on the set of variables and grooming methods that are
collectively known as "top taggers". To facilitate further exploration, we have
attempted to collect, harmonise, and publish software implementations of these
techniques.Comment: 53 pages, 17 figures. L. Asquith, S. Rappoccio, C. K. Vermilion,
editors; v2: minor edits from journal revision
The Effects of Fourth Generation on the double Lepton Polarization in B \rar K \ell^+ \ell^- decay
This study investigates the influence of the fourth generation quarks on the
double lepton polarizations in B \rar K \ell^+ \ell^- decay. Taking
|V_{t's}V_{t'b}|\sim \{0.01-0.03\} with phase about 100^\circ, which is
consistent with the b\to s\ell^+\ell^- rate and the B_s mixing parameter Delta
m_{B_s}$, we obtain that the double lepton(muon and tau) polarizations are
quite sensitive to the existence of fourth generation. It can serve as a good
tool to search for new physics effects, precisely, to indirect search for the
fourth generation quarks(t', b').Comment: 30 pages, 27 figure
Physics at a 100 TeV pp collider: beyond the Standard Model phenomena
This report summarises the physics opportunities in the search and study of
physics beyond the Standard Model at a 100 TeV pp collider.Comment: 196 pages, 114 figures. Chapter 3 of the "Physics at the FCC-hh"
Repor
Simplified Models for LHC New Physics Searches
This document proposes a collection of simplified models relevant to the
design of new-physics searches at the LHC and the characterization of their
results. Both ATLAS and CMS have already presented some results in terms of
simplified models, and we encourage them to continue and expand this effort,
which supplements both signature-based results and benchmark model
interpretations. A simplified model is defined by an effective Lagrangian
describing the interactions of a small number of new particles. Simplified
models can equally well be described by a small number of masses and
cross-sections. These parameters are directly related to collider physics
observables, making simplified models a particularly effective framework for
evaluating searches and a useful starting point for characterizing positive
signals of new physics. This document serves as an official summary of the
results from the "Topologies for Early LHC Searches" workshop, held at SLAC in
September of 2010, the purpose of which was to develop a set of representative
models that can be used to cover all relevant phase space in experimental
searches. Particular emphasis is placed on searches relevant for the first
~50-500 pb-1 of data and those motivated by supersymmetric models. This note
largely summarizes material posted at http://lhcnewphysics.org/, which includes
simplified model definitions, Monte Carlo material, and supporting contacts
within the theory community. We also comment on future developments that may be
useful as more data is gathered and analyzed by the experiments.Comment: 40 pages, 2 figures. This document is the official summary of results
from "Topologies for Early LHC Searches" workshop (SLAC, September 2010).
Supplementary material can be found at http://lhcnewphysics.or
Vacuum Instabilities with a Wrong-Sign Higgs-Gluon-Gluon Amplitude
The recently discovered 125 GeV boson appears very similar to a Standard
Model Higgs, but with data favoring an enhanced h to gamma gamma rate. A number
of groups have found that fits would allow (or, less so after the latest
updates, prefer) that the h-t-tbar coupling have the opposite sign. This can be
given meaning in the context of an electroweak chiral Lagrangian, but it might
also be interpreted to mean that a new colored and charged particle runs in
loops and produces the opposite-sign hGG amplitude to that generated by
integrating out the top, as well as a contribution reinforcing the W-loop
contribution to hFF. In order to not suppress the rate of h to WW and h to ZZ,
which appear to be approximately Standard Model-like, one would need the loop
to "overshoot," not only canceling the top contribution but producing an
opposite-sign hGG vertex of about the same magnitude as that in the SM. We
argue that most such explanations have severe problems with fine-tuning and,
more importantly, vacuum stability. In particular, the case of stop loops
producing an opposite-sign hGG vertex of the same size as the Standard Model
one is ruled out by a combination of vacuum decay bounds and LEP constraints.
We also show that scenarios with a sign flip from loops of color octet charged
scalars or new fermionic states are highly constrained.Comment: 20 pages, 8 figures; v2: references adde
Boosted Semileptonic Tops in Stop Decays
Top partner searches are one of the key aspects of new physics analyses at
the LHC. We correct an earlier statement that supersymmetric top searches based
on decays to semileptonic tops are not promising. Reconstructing the direction
of the boosted leptonic top quark and correlating it with the measured missing
transverse energy vector allows us to reduce the top pair background to an
easily manageable level. In addition, reconstructing the full momentum of the
leptonic top quark determines the stop mass based on an M_{T2} endpoint.Comment: 14pages, 4 figue
The CLIC Potential for New Physics
The Compact Linear Collider (CLIC) is a mature option for the future of high
energy physics. It combines the benefits of the clean environment of
colliders with operation at high centre-of-mass energies, allowing to probe
scales beyond the reach of the Large Hadron Collider (LHC) for many scenarios of new physics. This places the CLIC project at a privileged spot in between the precision and energy frontiers, with capabilities that will significantly extend knowledge on both fronts at the end of the LHC era. In this report we review and revisit the potential of CLIC to search, directly and indirectly, for physics beyond the Standard Model
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