897 research outputs found
(Pseudo)-Dirac neutrinos and leptogenesis
We discuss how Dirac neutrinos can naturally be generated in supersymmetry
and how they allow for an Affleck-Dine leptogenesis scenario, in which a
left-right asymmetry is generated in the sneutrino sector, the left part of
which is transferred to a baryon asymmetry via sphaleron transitions. No exotic
fields need to be added to the MSSM other than the right-handed neutrino.Comment: 7 pages, 1 figure, Talk given at the Dark Side of the Universe
Conference 2006 (DSU2006), Madrid, Spain, 20-24 June 200
On Metastability in Supersymmetric Models
We make a critical reappraisal of `unbounded-from-below' (UFB) constraints in
the MSSM and R-parity violating models. We explain why the `traditional' UFB
bounds are neither necessary nor sufficient and propose, instead, a sufficient
condition which ensures that there are no local minima along the flat
directions. This conservative (but meaningful) condition divides the parameter
space into regions which are allowed, regardless of cosmology, and regions in
which cosmology is expected to play a major role. We study both conditions at
low tan-beta and obtain analytic approximations to the UFB bounds for all low
tan-beta (<15). Finally we show that R-parity violation just below current
experimental limits avoids UFB problems by lifting the dangerous flat
directions.Comment: 28 Pages plain latex; includes 4 eps figures, numerical errors
corrected plus additional reference, final version to appear in Nucl Phys
Hagedorn inflation of D-branes
We examine the cosmological effects of the Hagedorn phase in models where the
observable universe is pictured as a D-brane. It is shown that, even in the
absence of a cosmological constant, winding modes cause a negative `pressure'
that can drive brane inflation of various types including both power law and
exponential. We also find regimes in which the cosmology is stable but
oscillating (a bouncing universe) with the Hagedorn phase softening the
singular behavior associated with the collapse.Comment: 44 Pages; JHEP latex; includes 1 postscript figur
Anxiety Sensitivity in Adults with Body Focused Repetitive Behaviors
Body focused repetitive behaviors (BFRBs) such as hair pulling, skin picking, and nail biting
affect almost 4% of the general population (Rasmussen & Eisen, 1992), but the factors that
predispose individuals to these behaviors are poorly understood. BFRBs are associated with
maladaptive emotional regulation (Diefenbach, Tolin, Meunier, & Worhunsky, 2008; Roberts,
O’Connor, & Bélanger, 2013), whereby symptoms serve to temporarily attenuate aversive
affective experiences. One particular mechanism through which emotion dysregulation may
manifest in persons with BFRBs is anxiety sensitivity, which is defined as the fear of one’s own
experiences (Reiss and McNally, 1985; Teng, Woods, Twohig, & Marcks, 2002). The current
study aimed to determine whether anxiety sensitivity is elevated among adults with BFRBs
compared to adults without BFRBs, and whether anxiety sensitivity severity is associated with
BFRB symptom severity. Furthermore, anxiety sensitivity levels between different forms of
BFRBs will be explored. Participants were recruited via BFRB patient advocacy websites and
mailing lists (e.g. the Trichotillomania Learning Center; www.tlc.org) and completed online self-
report surveys. Results indicated that clinical BFRBs had higher AS than the general population
and that there were no significant differences in AS between persons with ExD and TTM. Future
research should look into the underlying mechanisms of AS in BFRBs and how to treat it
Framework for an asymptotically safe standard model via dynamical breaking
We present a consistent embedding of the matter and gauge content of the Standard Model into an underlying asymptotically safe theory that has a well-determined interacting UV fixed point in the large color/flavor limit. The scales of symmetry breaking are determined by two mass-squared parameters with the breaking of electroweak symmetry being driven radiatively. There are no other free parameters in the theory apart from gauge couplings
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