6,767 research outputs found
Properties of Discrete Black Hole Hair
We revisit the physical effects of discrete gauge charge on
black hole thermodynamics, building on the seminal work of Coleman, Preskill,
and Wilczek. Realising the discrete theory from the spontaneous breaking of an
Abelian gauge theory, we consider the two limiting cases of interest, depending
on whether the Compton wavelength of the massive vector is much smaller or much
larger than the size of the black hole -- the so-called thin- and thick-string
limits respectively. We find that the qualitative effect of discrete hair on
the mass-temperature relationship is the same in both regimes, and similar to
that of unbroken charge: namely, a black hole carrying discrete gauge
charge is always colder than its uncharged counterpart. In the thick-string
limit, our conclusions bring into question some of the results of Coleman et
al., as we discuss. Further, by considering the system to be enclosed within a
finite cavity, we argue how the unbroken limit may be smoothly defined, and the
unscreened electric field of the standard Reissner-Nordstrom solution
recovered.Comment: 19 pages, 5 figures; references added, matches published versio
LHCb anomalies from a natural perspective
Tension between the Standard Model (SM) and data concerning
processes has become apparent. Most notoriously, concerning the ratio,
which probes lepton non-universality in decays, and measurements involving
the decays and . Careful analysis of a wide range of data shows that
certain kinds of new physics can significantly ameliorate agreement with
experiment. Here, we show that these anomalies can be
naturally accommodated in the context of Natural Scherk-Schwarz Theories of the
Weak Scale -- a class of models designed to address the hierarchy problem. No
extra states need to be introduced in order to accommodate these anomalies, and
the assumptions required regarding flavor violating couplings are very mild.
Moreover, the structure of the theory makes sharp predictions regarding
meson decays into final states including pairs, which will
provide a future test of these models.Comment: 14 pages plus appendices, 3 figures; references added, published in
JHE
Rescuing Massive Photons from the Swampland
Stringent Swampland conjectures aimed at effective theories containing
massive abelian vectors have recently been proposed (arXiv:1808.09966), with
striking phenomenological implications. In this article, we show how effective
theories that parametrically violate the proposed conjectures can be
UV-completed into theories that satisfy them. The UV-completion is accessible
through both the St\"uckelberg and Higgs mechanisms, with all dimensionless
parameters taking values from the UV perspective. These
constructions feature an IR limit containing a light vector that is
parametrically separated from any other massive states, and from any cut-off
scale mandated by quantum gravity consistency requirements. Moreover, the
cut-off--to--vector--mass ratio remains parametrically large even in the
decoupling limit in which all other massive states (including any scalar
excitations) become arbitrarily heavy. We discuss how apparently strong
constraints imposed by the proposed conjectures on phenomenologically
interesting models, including specific production mechanisms of dark photon
dark matter, are thereby circumvented.Comment: 15 page
Disassembling the Clockwork Mechanism
The clockwork mechanism is a means of naturally generating exponential
hierarchies in theories without significant hierarchies among fundamental
parameters. We emphasize the role of interactions in the clockwork mechanism,
demonstrating that clockwork is an intrinsically abelian phenomenon precluded
in non-abelian theories such as Yang-Mills, non-linear sigma models, and
gravity. We also show that clockwork is not realized in extra-dimensional
theories through purely geometric effects, but may be generated by appropriate
localization of zero modes.Comment: 30 pages plus appendices, 4 figures. v2: Clarifications, minor
changes, and comment on 1705.10162 added. Conclusions unchange
Natural Scherk-Schwarz Theories of the Weak Scale
Natural supersymmetric theories of the weak scale are under growing pressure
given present LHC constraints, raising the question of whether untuned
supersymmetric (SUSY) solutions to the hierarchy problem are possible. In this
paper, we explore a class of 5-dimensional natural SUSY theories in which SUSY
is broken by the Scherk-Schwarz mechanism. We pedagogically explain how
Scherk-Schwarz elegantly solves the traditional problems of 4-dimensional SUSY
theories (based on the MSSM and its many variants) that usually result in an
unsettling level of fine-tuning. The minimal Scherk-Schwarz set up possesses
novel phenomenology, which we briefly outline. We show that achieving the
observed physical Higgs mass motivates extra structure that does not
significantly affect the level of tuning (always better than ) and
we explore three qualitatively different extensions: the addition of extra
matter that couples to the Higgs, an extra gauge group under
which the Higgs is charged and an NMSSM-like solution to the Higgs mass
problem.Comment: 36 pages + appendix, 12 figure
Compensation and speed of advancement in executive careers through the internal and external labor markets by gender
Our study aims at exploring whether
internal and external moves have a different impact on the speed of advancement in
executive careers, identifying gender differences in the influence of both mobility routes
and understanding the impact of speed on compensation inequality.Universidad de Málaga. Campus de Excelencia Internacional AndalucÃa Tech
Brief pain inventory (elderly): short form
This issue of eMedRef provides information to clinicians on the short form used to assess pain in the elderly
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