435 research outputs found
Determining R-parity violating parameters from neutrino and LHC data
In supersymmetric models neutrino data can be explained by R-parity violating
operators which violate lepton number by one unit. The so called bilinear model
can account for the observed neutrino data and predicts at the same time
several decay properties of the lightest supersymmetric particle. In this paper
we discuss the expected precision to determine these parameters by combining
neutrino and LHC data and discuss the most important observables. We show that
one can expect a rather accurate determination of the underlying R-parity
parameters assuming mSUGRA relations between the R-parity conserving ones and
discuss briefly also the general MSSM as well as the expected accuracies in
case of a prospective e+ e- linear collider. An important observation is that
several parameters can only be determined up to relative signs or more
generally relative phases.Comment: 13 pages, 13 figure
Bilinear R-parity violation with flavor symmetry
Bilinear R-parity violation (BRPV) provides the simplest intrinsically
supersymmetric neutrino mass generation scheme. While neutrino mixing
parameters can be probed in high energy accelerators, they are unfortunately
not predicted by the theory. Here we propose a model based on the discrete
flavor symmetry with a single R-parity violating parameter, leading to
(i) correct Cabbibo mixing given by the Gatto-Sartori-Tonin formula, and a
successful unification-like b-tau mass relation, and (ii) a correlation between
the lepton mixing angles and in agreement with
recent neutrino oscillation data, as well as a (nearly) massless neutrino,
leading to absence of neutrinoless double beta decay.Comment: 16 pages, 3 figures. Extended version, as published in JHE
Displaced Supersymmetry
The apparent absence of light superpartners at the LHC strongly constrains
the viability of the MSSM as a solution to the hierarchy problem. These
constraints can be significantly alleviated by R-parity violation (RPV).
Bilinear R-parity violation, with the single operator L H_u, does not require
any special flavor structure and can be naturally embedded in a GUT while
avoiding constraints from proton decay (unlike baryon-number-violating RPV).
The LSP in this scenario can be naturally long-lived, giving rise to displaced
vertices. Many collider searches, particularly those selecting b-jets or
leptons, are insensitive to events with such detector-scale displaced decays
owing to cuts on track quality and impact parameter. We demonstrate that for
decay lengths in the window ~1-1000 mm, constraints on superpartner masses can
be as low as ~450 GeV for squarks and ~40 GeV for LSPs. In some parts of
parameter space light LSPs can dominate the Higgs decay width, hiding the Higgs
from existing searches. This framework motivates collider searches for
detector-scale displaced vertices. LHCb may be ideally suited to trigger on
such events, while ATLAS and CMS may need to trigger on missing energy in the
event.Comment: 35 pages, 4 figure
Stochastic Gravity: Theory and Applications
Whereas semiclassical gravity is based on the semiclassical Einstein equation
with sources given by the expectation value of the stress-energy tensor of
quantum fields, stochastic semiclassical gravity is based on the
Einstein-Langevin equation, which has in addition sources due to the noise
kernel.In the first part, we describe the fundamentals of this new theory via
two approaches: the axiomatic and the functional. In the second part, we
describe three applications of stochastic gravity theory. First, we consider
metric perturbations in a Minkowski spacetime: we compute the two-point
correlation functions for the linearized Einstein tensor and for the metric
perturbations. Second, we discuss structure formation from the stochastic
gravity viewpoint. Third, we discuss the backreaction of Hawking radiation in
the gravitational background of a quasi-static black hole.Comment: 75 pages, no figures, submitted to Living Reviews in Relativit
Radiative contribution to neutrino masses and mixing in SSM
In an extension of the minimal supersymmetric standard model (popularly known
as the SSM), three right handed neutrino superfields are introduced to
solve the -problem and to accommodate the non-vanishing neutrino masses
and mixing. Neutrino masses at the tree level are generated through parity
violation and seesaw mechanism. We have analyzed the full effect of one-loop
contributions to the neutrino mass matrix. We show that the current three
flavour global neutrino data can be accommodated in the SSM, for both
the tree level and one-loop corrected analyses. We find that it is relatively
easier to accommodate the normal hierarchical mass pattern compared to the
inverted hierarchical or quasi-degenerate case, when one-loop corrections are
included.Comment: 51 pages, 14 figures (58 .eps files), expanded introduction, other
minor changes, references adde
Exploring novel correlations in trilepton channels at the LHC for the minimal supersymmetric inverse seesaw model
We investigate signatures of the minimal supersymmetric inverse seesaw model
at the large hadron collider (LHC) with three isolated leptons and large
missing energy (3\ell + \mET or 2\ell + 1\tau + \mET, with \ell=e,\mu) in the
final state. This signal has its origin in the decay of chargino-neutralino
(\chpm1\ntrl2) pair, produced in pp collisions. The two body decays of the
lighter chargino into a charged lepton and a singlet sneutrino has a
characteristic decay pattern which is correlated with the observed large
atmospheric neutrino mixing angle. This correlation is potentially observable
at the LHC by looking at the ratios of cross sections of the trilepton + \mET
channels in certain flavour specific modes. We show that even after considering
possible leading standard model backgrounds these final states can lead to
reasonable discovery significance at the LHC with both 7 TeV and 14 TeV
center-of-mass energy.Comment: 28 pages, 9 .eps figures. 3 new figures and discussions on LHC
observables added, minor modifications in text and in the abstract, 23 new
references added, matches with the published version in JHE
Hamilton depression rating scale and montgomery–asberg depression rating scale in depressed and bipolar I patients: psychometric properties in a Brazilian sample
Stochastic Gravity: Theory and Applications
Whereas semiclassical gravity is based on the semiclassical Einstein equation
with sources given by the expectation value of the stress-energy tensor of
quantum fields, stochastic semiclassical gravity is based on the
Einstein-Langevin equation, which has in addition sources due to the noise
kernel. In the first part, we describe the fundamentals of this new theory via
two approaches: the axiomatic and the functional. In the second part, we
describe three applications of stochastic gravity theory. First, we consider
metric perturbations in a Minkowski spacetime, compute the two-point
correlation functions of these perturbations and prove that Minkowski spacetime
is a stable solution of semiclassical gravity. Second, we discuss structure
formation from the stochastic gravity viewpoint. Third, we discuss the
backreaction of Hawking radiation in the gravitational background of a black
hole and describe the metric fluctuations near the event horizon of an
evaporating black holeComment: 100 pages, no figures; an update of the 2003 review in Living Reviews
in Relativity gr-qc/0307032 ; it includes new sections on the Validity of
Semiclassical Gravity, the Stability of Minkowski Spacetime, and the Metric
Fluctuations of an Evaporating Black Hol
Factors Associated with Colposcopy-Histopathology Confirmed Cervical Intraepithelial Neoplasia among HIV-Infected Women from Rio De Janeiro, Brazil
Introduction: Despite the availability of preventive strategies (screening tests and vaccines), cervical cancer continues to
impose a significant health burden in low- and medium-resourced countries. HIV-infected women are at increased risk for
infection with human papillomavirus (HPV) and thus development of cervical squamous intraepithelial neoplasia (CIN).
Methods:Study participants included HIV-infected women enrolling the prospective open cohort of Evandro Chagas
Clinical Research Institute, Oswaldo Cruz Foundation (IPEC/FIOCRUZ). At cohort entry, women were subjected to
conventional Papanicolaou test, HPV-DNA test and colposcopy; lesions suspicious for CIN were biopsied. Histopathology
report was based on directed biopsy or on specimens obtained by excision of the transformation zone or cervical
conization. Poisson regression modeling was used to assess factors associated with CIN2+diagnosis.
Results:The median age of the 366 HIV-infected women included in the study was 34 years (interquartile range: 28–41
years). The prevalence of CIN1, CIN2 and CIN3 were 20.0%, 3.5%, and 2.2%, respectively. One woman was found to have
cervical cancer. The prevalence of CIN2+was 6.0%. Factors associated with CIN2+diagnosis in the multivariate model were
age,years compared to350 cells/mm3 (aPR = 6.03 95%CI 1.50–24.3) and concomitant
diagnosis of vulvar and/or vaginal intraepithelial lesion (aPR = 2.68 95%CI 0.99–7.24).
Discussion:Increased survival through wide-spread use of highly active antiretroviral therapy might allow for the
development of cervical cancer. In Brazil, limited cytology screening and gynecological care adds further complexity to the
HIV-HPV co-infection problem. Integrated HIV care and cervical cancer prevention programs are needed for the prevention
of cervical cancer mortality in this group of wome
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