13 research outputs found
Precision unification and the scale of supersymmetry
In this letter, we study the implications of precise gauge coupling
unification on supersymmetric particle masses. We argue that precise
unification favors the superpartner masses that are in the range of several TeV
and well beyond. We demonstrate this in the minimal supersymmetric theory with
a common sparticle mass threshold, and two simple high-scale scenarios: minimal
supergravity and minimal anomaly-mediated supersymmetry. We also identify
candidate models with a Higgsino or a wino dark matter candidate. Finally, the
analysis shows unambiguously that unless one takes foggy naturalness notions
too seriously, the lack of direct superpartner discoveries at the LHC has not
diminished the viability of supersymmetric unified theories in general nor even
precision unification in particular.Comment: 6 pages, 3 figure
Isosinglet vectorlike leptons at colliders
We study weak isosinglet vectorlike leptons that decay through a small mixing
with the tau lepton, for which the discovery and exclusion reaches of the Large
Hadron Collider and future proposed hadron colliders are limited. We show how
an collider may act as a discovery machine for these
particles, demonstrate that the mass peak can be reconstructed
in a variety of distinct signal regions, and explain how the
branching ratios may be measured.Comment: 34 pages, 13 figure
Statistical significances and projections for proton decay experiments
We study the statistical significances for exclusion and discovery of proton
decay at current and future neutrino detectors. Various counterintuitive flaws
associated with frequentist and modified frequentist statistical measures of
significance for multi-channel counting experiments are discussed in a general
context and illustrated with examples. We argue in favor of conservative
Bayesian-motivated statistical measures, and as an application we employ these
measures to obtain the current lower limits on proton partial lifetime at
various confidence levels, based on Super-Kamiokande's data, generalizing the
90\% CL published limits. Finally, we present projections for exclusion and
discovery reaches for proton partial lifetimes in and decay channels at Hyper-Kamiokande, DUNE,
JUNO, and THEIA.Comment: 58 pages. v2: published in PRD with minor revision
Freezing-in hadrophilic dark matter at low reheating temperatures
If the reheating temperature at the end of inflation is low, of order 10 MeV,
then dark matter produced through ultraviolet freeze-in has a large direct
detection cross section. We study such a scenario in which dark matter is
hadrophilic. This leads to dark matter-nucleon scattering cross sections of
interest for near-future experiments for dark matter masses in the range of 100
keV-100 MeV. We explore how these predictions vary if reheating is
non-instantaneous.Comment: 17+8 pages, 7 figure
Criteria for projected discovery and exclusion sensitivities of counting experiments
The projected discovery and exclusion capabilities of particle physics and
astrophysics/cosmology experiments are often quantified using the median
expected -value or its corresponding significance. We argue that this
criterion leads to flawed results, which for example can counterintuitively
project lessened sensitivities if the experiment takes more data or reduces its
background. We discuss the merits of several alternatives to the median
expected significance, both when the background is known and when it is subject
to some uncertainty. We advocate for standard use of the "exact Asimov
significance" detailed in this paper.Comment: 10 pages. v2: new information about the extreme no-background limit
included, two new figures added, other minor change
The depleted Higgs boson: searches for universal coupling suppression, invisible decays, and mixed-in scalars
There are two simple ways that the standard signals of the Standard Model
Higgs boson can be depleted. Its couplings to fermions and gauge bosons can be
suppressed by a universal factor, and part of its branching fraction can be
drained into invisible final states. A large class of theories can impose one
or both of these depletion factors, even if mild, by way of additional scalar
bosons that are singlets under the Standard Model but mix with the Higgs boson.
We perform a comprehensive survey of the present status of the depleted Higgs
boson, and discuss future prospects for detecting the presence of either
depletion factor. We also survey the constraints status and future detection
prospects for the generic case of extra mixed-in scalars which generically lead
to these depletion factors for the Higgs boson. We find, for example, that
precision study of the Higgs boson in many cases is more powerful than searches
for the extra scalar states, given the slate of next-generation experiments
that are on the horizon.Comment: 24 pages, 7 figures. v2: minor change
Signal-background interference for digluon resonances at the Large Hadron Collider
We study the interference between the amplitudes for gg→X→gg, where X is a new heavy digluon resonance, and the QCD background gg→gg, at the Large Hadron Collider. The interference produces a large low-mass tail and a deficit of events above the resonance mass, compared to the naive pure-resonance peak. For a variety of different resonance quantum numbers and masses, we evaluate the signal-background interference contribution at leading order, including showering, hadronization, and detector effects. The resulting new physics dijet mass distribution may have a shape that appears, after QCD background fitting and subtraction, to resemble an enhanced peak, a shelf, a peak/dip, or even a pure dip. We argue that the true limits on new digluon resonances are likely to differ significantly from the limits obtained when interference is neglected, especially if the branching ratio to gg is less than 1.We study the interference between the amplitudes for , where is a new heavy digluon resonance, and the QCD background , at the Large Hadron Collider. The interference produces a large low-mass tail and a deficit of events above the resonance mass, compared to the naive pure resonance peak. For a variety of different resonance quantum numbers and masses, we evaluate the signal-background interference contribution at leading order, including showering, hadronization, and detector effects. The resulting new physics dijet mass distribution may have a shape that appears, after QCD background fitting and subtraction, to resemble an enhanced peak, a shelf, a peak/dip, or even a pure dip. We argue that the true limits on new digluon resonances are likely to differ significantly from the limits obtained when interference is neglected, especially if the branching ratio to is less than 1
Report of the Topical Group on Physics Beyond the Standard Model at Energy Frontier for Snowmass 2021
This is the Snowmass2021 Energy Frontier (EF) Beyond the Standard Model (BSM) report. It combines the EF topical group reports of EF08 (Model-specific explorations), EF09 (More general explorations), and EF10 (Dark Matter at Colliders). The report includes a general introduction to BSM motivations and the comparative prospects for proposed future experiments for a broad range of potential BSM models and signatures, including compositeness, SUSY, leptoquarks, more general new bosons and fermions, long-lived particles, dark matter, charged-lepton flavor violation, and anomaly detection