277 research outputs found
Experiments and Simulations of short-pulse laser-pumped extreme ultraviolet lasers
Recent experimental work on the development of extreme ultraviolet lasers undertaken using as the pumping source the VULCAN laser at the Rutherford Appleton Laboratory is compared to detailed simulations. It is shown that short duration (similar topicosecond) pumping can produce X-ray laser pulses of a few picosecond duration and that measurement of the emission from the plasma can give an estimate of the duration of the gain coefficient. The Ehybrid fluid and atomic physics code developed at the University of York is used to simulate X-ray laser gain and plasma emission. Two postprocessors to the Ehybrid code are utilized: 1) to raytrace the X-ray laser beam amplification and refraction and 2) to calculate the radiation emission in the kiloelectronvolt photon energy range. The raytracing and spectral simulations are compared, respectively, to measured X-ray laser output and the output of two diagnostics recording transverse X-ray emission. The pumping laser energy absorbed in the plasma is examined by comparing the simulations to experimental results. It is shown that at high pumping irradiance (>10(15) Wcm(-2)), fast electrons are produced by parametric processes in the preformed long scale-length plasmas. These fast electrons do not pump the population inversion and so pumping efficiency is reduced at high irradiance
Flavour-Conserving CP Phases in Supersymmetry and Implications for Exclusive B Decays
We study rare exclusive B decays based on the quark-level transition
b->s(d)l^+l^-, where l=e or mu, in the context of supersymmetric theories with
minimal flavour violation. We present analytic expressions for various mixing
matrices in the presence of new CP-violating phases, and examine their impact
on observables involving B and \bar{B} decays. An estimate is obtained for
CP-violating asymmetries in B->K^(*)l^+l^- and B->rho(pi)l^+l^- decays for the
dilepton invariant mass region 1.2 GeV < M_{l^+l^-}< M_{J/psi}. As a typical
result, we find a CP-violating partial width asymmetry of about -6% (-5%) in
the case of B->pi (B->rho) in effective supersymmetry with phases of O(1),
taking into account the measurement of the inclusive b->s gamma branching
fraction. On the other hand, CP asymmetries of less than 1% are predicted in
the case of B->K^(*). We argue that it is not sufficient to have additional CP
phases of O(1) to observe large CP-violating effects in exclusive b->s(d)l^+l^-
decays.Comment: 34 pages, REVTeX, 6 figures, final version to appear in Phys. Rev. D,
with some minor addition
Higgs for Graviton: Simple and Elegant Solution
A Higgs mechanism for gravity is presented, where four scalars with global
Lorentz symmetry are employed. We show that in the broken symmetry phase a
graviton absorbs all scalars and become massive spin 2 particle with five
degrees of freedom. The resulting theory is unitary and free of ghosts.Comment: 8 pages, References added. The decoupling of ghost state is analyzed
in detail
Minimal Flavour Violation: an effective field theory approach
We present a general analysis of extensions of the Standard Model which
satisfy the criterion of Minimal Flavour Violation (MFV). We define this
general framework by constructing a low-energy effective theory containing the
Standard Model fields, with one or two Higgs doublets and, as the only source
of SU(3)^5 flavour symmetry breaking, the background values of fields
transforming under the flavour group as the ordinary Yukawa couplings. We
analyse present bounds on the effective scale of dimension-six operators, which
range between 1 and 10 TeV, with the most stringent constraints imposed by B ->
X_s gamma. In this class of theories, it is possible to relate predictions for
FCNC processes in B physics to those in K physics. We compare the sensitivity
of various experimental searches in probing the hypothesis of MFV. Within the
two-Higgs-doublet scenario, we develop a general procedure to obtain all
tan(beta)-enhanced Higgs-mediated FCNC amplitudes, discussing in particular
their impact in B -> l^+l^-, Delta M_B and B -> X_s gamma. As a byproduct, we
derive some two-loop tan(beta)-enhanced supersymmetric contributions to B ->
X_s gamma previously unknown.Comment: 32 pages, 6 figures. Version 2: new section discussing MFV in
supersymmetric models added; updated experimental data; few minor change
Assessment of proportion of hidden patients having symptoms of overactive bladder and why has it been hidden in female outpatients admitted to hospital
Purpose: To determine the proportion of patients with undetected symptoms of overactive bladder by using the overactive bladder-validated 8 (OAB-V8) screening questionnaire and investigate these symptoms were undetected in female patients who were hospitalized. Methods: We invited 2,250 female patients hospitalized in the Aegean region of Turkey to answer a self-administered questionnaire. The questionnaire included questions on evidence of lower urinary tract symptoms (OAB-V8), relevant medical history, and demographic data. Patients with a total OAB-V8 score ≥ 8 were defined as having OAB symptoms. Results: The proportion of patients with OAB symptoms in this study was 40.6%. Nearly 57% of the patients with OAB symptoms had not been previously admitted to any hospital for lower urinary tract symptoms (LUTS). The two most common reasons why women with OAB symptoms did not admit themselves to a hospital because of LUTS were as follows: "I did not think I had a disease" and "The symptoms did not bother me," with a response rate of 74.7%. The mean OAB-V8 scores of the patients with these two responses were significantly lower than those of the other patients (P < 0.001). Conclusions: This is the first study to demonstrate a significant proportion of women with undetected OAB symptoms. The main reasons the women did not admit themselves to a hospital were their unawareness of the disease and because the LUTS were not bothersome. Public awareness programs on this disease may resolve this problem. © 2016 Korean Continence Society
B -> X_s gamma in Supersymmetry with Explicit CP Violation
We discuss B -> X_s gamma decay in both constrained and unconstrained
supersymmetric models with explicit CP violation within the minimal flavor
violation scheme by including tan(beta) -enhanced large contributions beyond
the leading order. In this analysis, we take into account the relevant
cosmological and collider bounds, as well as electric dipole moment
constraints. In the unconstrained model, there are portions of the parameter
space yielding a large CP asymmetry at leading order (LO). In these regions, we
find that the CP phases satisfy certain sum rules, e.g., the sum of the phases
of the \mu parameter and the stop trilinear coupling centralize around \pi with
a width determined by the experimental bounds. In addition, at large values of
tan(beta), the sign of the CP asymmetry tracks the sign of the gluino mass, and
the CP asymmetry is significantly larger than the LO prediction. In the
constrained minimal supersymmetric standard model based on minimal
supergravity, we find that the decay rate is sensitive to the phase of the
universal trilinear coupling. This sensitivity decreases at large values of the
universal gauino mass. We also show that for a given set of the mass
parameters, there exists a threshold value of the phase of the universal
trilinear coupling which grows with tan(beta) and beyond which the experimental
bounds are satisfied. In both supersymmetric scenarios, the allowed ranges of
the CP phases are wide enough to have phenomenological consequences.Comment: 25 pages, 11 figures. Added references, made minor changes in the
text; journal versio
B decays and Supersymmetry
I discuss how supersymmetry affects various observables in B decays, and
point out the interesting channels in the context of B factories.Comment: LaTex file of working group talk presented at WHEPP-7, HRI,
Allahabad, Jan. 200
Loop-Induced CP Violation in the Gaugino and Higgsino Sectors of Supersymmetric Theories
We show that the gaugino and higgsino sectors of supersymmetric theories can
naturally acquire observable CP violation through radiative effects which
originate from large CP-violating trilinear couplings of the Higgs bosons to
the third-generation scalar quarks. These CP-violating loop effects are not
attainable by evolving the supersymmetric renormalization-group equations from
a higher unification scale down to the electroweak one. We briefly discuss the
phenomenological consequences of such a scenario, and as an example, calculate
the two-loop contribution to the neutron electric dipole moment generated by
the one-loop chromo-electric dipole moment of the gluino.Comment: 9 pages, as to appear in Physical Review
MSSM Higgs-Boson Production at Hadron Colliders with Explicit CP Violation
Gluon fusion is the main production mechanism for Higgs bosons with masses up
to several hundred GeV in collisions at the CERN Large Hadron Collider. We
investigate the effects of the CP-violating phases on the fusion process
including both the sfermion-loop contributions and the one-loop induced
CP-violating scalar-pseudoscalar mixing in the minimal supersymmetric standard
model. With a universal trilinear parameter assumed, every physical observable
involves only the sum of the phases of the universal trilinear parameter
and the higgsino mass parameter . The phase affects the lightest
Higgs-boson production rate significantly through the neutral Higgs-boson
mixing and, for the masses around the lightest stop-pair threshold, it also
changes the production rate of the heavy Higgs bosons significantly through
both the stop and sbottom loops and the neutral Higgs-boson mixing.Comment: 28 pages, 8 figures. Some references and comments added. Typos
corrected. To appear in Phys. Rev.
Lepton polarization asymmetry in radiative dileptonic B-meson decays in MSSM
In this paper we study the polarization asymmetries of the final state lepton
in the radiative dileptonic decay of B meson (\bsllg) in the framework of
Minimal Supersymmetric Standard Model (MSSM) and various other unified models
within the framework of MSSM e.g. mSUGRA, SUGRA (where condition of
universality of scalar masses is relaxed) etc. Lepton polarization, in addition
of having a longitudinal component (\pl), can have two other components, \pt
and \pn, lying in and perpendicular to the decay plane, which are proportional
to \ml and hence are significant for final state being or
. We analyse the dependence of these polarization asymmetries
on the parameters of the various models.Comment: typos corrected to match with published versio
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