2,709 research outputs found
Rare Top-quark Decays to Higgs boson in MSSM
In full one-loop generality and in next-to-leading order in QCD, we study
rare top to Higgs boson flavour changing decay processes with
quarks, in the general MSSM with R-parity conservation. Our primary
goal is to search for enhanced effects on that could be visible
at current and high luminosity LHC running. To this end, we perform an
analytical expansion of the amplitude in terms of flavour changing squark mass
insertions that treats both cases of hierarchical and degenerate squark masses
in a unified way. We identify two enhanced effects allowed by various
constraints: one from holomorphic trilinear soft SUSY breaking terms and/or
right handed up squark mass insertions and another from non-holomorphic
trilinear soft SUSY breaking terms and light Higgs boson masses. Interestingly,
even with flavour violating effects in the, presently
unconstrained, up-squark sector, SUSY effects on come out to be
unobservable at LHC mainly due to leading order cancellations between penguin
and self energy diagrams and the constraints from charge- and colour-breaking
minima (CCB) of the MSSM vacuum. An exception to this conclusion may be effects
arising from non-holomorphic soft SUSY breaking terms in the region where the
CP-odd Higgs mass is smaller than the top-quark mass but this scenario is
disfavoured by recent LHC searches. Our calculations for decay are
made available in SUSY_FLAVOR numerical library.Comment: 32 pages, 6 figures; version accepted for publication in JHEP:
additional comparison with literature added, minor misprints correcte
Mass Insertions vs. Mass Eigenstates calculations in Flavour Physics
We present and prove a theorem of matrix analysis, the Flavour Expansion
Theorem (or FET), according to which, an analytic function of a Hermitian
matrix can be expanded polynomially in terms of its off-diagonal elements with
coefficients being the divided differences of the analytic function and
arguments the diagonal elements of the Hermitian matrix. The theorem is
applicable in case of flavour changing amplitudes. At one-loop level this
procedure is particularly natural due to the observation that every loop
function in the Passarino-Veltman basis can be recursively expressed in terms
of divided differences. FET helps to algebraically translate an amplitude
written in mass eigenbasis into flavour mass insertions, without performing
diagrammatic calculations in flavour basis. As a non-trivial application of FET
up to a third order, we demonstrate its use in calculating strong bounds on the
real parts of flavour changing mass insertions in the up- squark sector of the
MSSM from neutron Electric Dipole Moment (nEDM) measurements, assuming that
CP-violation arises only from the CKM matrix.Comment: 23 page
Bilateral pectoral musculature malformations with concomitant vascular anomaly
We report on a unique combination of multiple variations concerning the pectoral
muscles and the left external jugular vein. Specifically, a bilateral hypoplasia
of the medial clavicular portion of the pectoralis major muscle was noticed
along with the coexistence of total right pectoralis minor aplasia, substituted
by loose connective and fatty tissue. Simultaneously, a supernumerary
anterior-placed external jugular vein was found, which, after its supraclavicular
course, pierced the interval between the left clavicular and the sternocostal
head, and drained into the left jugular junction. The combination of the above
anomalies constitutes an atypical pattern of Poland syndrome. We discuss the
related embryological development and the relative literature. Attention was
paid to the clinical importance for plastic surgeons, general surgeons, and
radiologists, facilitating them with accurate interpretation of anterior thoracic
wall findings. (Folia Morphol 2010; 69, 3: 187-191
The density of virialized clusters as a probe of dark energy
We use the spherical collapse model to demonstrate that the observable
average density of virialized clusters depends on the properties of dark energy
along with the properties of gravity on cluster scales and can therefore be
used as a probe of these properties. As an application of this approach we
derive the predicted virialized densities and radii of cluster mass structures
for a wide range of values of the cosmological constant (including negative
values) as a function of the turnaround redshift. For the value of
(with ) preferred by
sign-switching models () proposed for the resolution of
the Hubble and tensions, we find an amplification of the density of
virialized clusters which can be as large as compared to \plcdm for a
turnaround redshift . Such an amplification may lead
to more efficient early galaxy formation in this class of models in accordance
with the recent findings of JWST.Comment: 12 pages, 8 figure
Aligning strategy to threat: a baseline anti-terrorism strategy for hotels
Purpose – Although the threat of terrorist attacks is not a new phenomenon for hotels, limited
literature exists on measures that hotels can take to prevent them or limit their damage. The purpose
of this paper is to propose a baseline strategy to address this threat.
Design/methodology/approach – Using the terrorist attack cycle and the security function models
introduced in this paper, 19 hotel security experts, members of an international working group on
terrorism, were tasked to reach consensus on a baseline anti-terrorist strategy for a hotel. To reach this
consensus, the study employed the Nominal Group Technique.
Findings – The study presents a six-step baseline anti-terrorism strategy and a series of measures
and actions under each step. In the centre of this strategy lies the disruption of the terrorist attack
cycle.
Research limitations/implications – There are limitations inherent to the Nominal Group
Technique which may not allow the generalizability of the findings. However, every effort was made
to ensure the reliability and validity of the study.
Practical implications – The study suggests a shift from physical protection alone to a more
intelligence-led approach. Counter-surveillance, terrorist behavioral analysis, higher visibility of
security measures, stronger relationships with local community leaders, collaborative relationships
with emergency response agencies and strategic use of risk intelligence providers will have to take a
higher place in the agendas of hotel security departments.
Originality/value – The paper presents, for the first time, two models that industry practitioners
will find useful when designing security policies: the terrorist attack cycle and the security function
model. Each component of the proposed strategy provides a starting point for the design of security
strategies tailored on the security needs and budget of any hotel property
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