14,029 research outputs found
Higher Dimensional Operators in the MSSM
The origin and the implications of higher dimensional effective operators in
4-dimensional theories are discussed in non-supersymmetric and supersymmetric
cases. Particular attention is paid to the role of general,
derivative-dependent field redefinitions which one can employ to obtain a
simpler form of the effective Lagrangian. An application is provided for the
Minimal Supersymmetric Standard Model extended with dimension-five R-parity
conserving operators, to identify the minimal irreducible set of such operators
after supersymmetry breaking. Among the physical consequences of this set of
operators are the presence of corrections to the MSSM Higgs sector and the
generation of "wrong"-Higgs Yukawa couplings and fermion-fermion-scalar-scalar
interactions. These couplings have implications for supersymmetry searches at
the LHC.Comment: Contribution to the proceedings of the "Susy 2008" conference; (6
pages
Cryptanalysis of group-based key agreement protocols using subgroup distance functions
We introduce a new approach for cryptanalysis of key agreement protocols
based on noncommutative groups. This approach uses functions that estimate the
distance of a group element to a given subgroup. We test it against the
Shpilrain-Ushakov protocol, which is based on Thompson's group F
Dilepton production in nucleus-nucleus collisions at top SPS energy within the Parton-Hadron-String Dynamics (PHSD) transport approach
Dilepton production in In+In collisions at 158 AGeV is studied within the
microscopic parton-hadron-string dynamics (PHSD) transport approach that
incorporates explicit partonic degrees-of-freedom, dynamical hadronization as
well as the more familiar hadronic dynamics in the final reaction stages. A
comparison to the data of the NA60 Collaboration shows that the measured
dilepton yield is well described by including the collisional broadening of
vector mesons, while simultaneously accounting for the electromagnetic
radiation of the strongly coupled quark-gluon plasma (sQGP) via off-shell
quark-antiquark annihilation, quark annihilation with additional gluon
Bremsstrahlung and the gluon-Compton scattering mechanisms. In particular, the
spectra in the intermediate mass range (1 GeV < M < 2.5 GeV) are dominated by
quark-antiquark annihilation in the nonperturbative QGP. Also, the observed
softening of the transverse mass spectra at intermediate masses (1 GeV < M <
2.5 GeV) is approximately reproduced. Furthermore, for dileptons of low masses
(M < 0.6 GeV), we find a sizable contribution from the quark annihilation with
additional gluon bremsstrahlung, thus providing another possible window for
probing the properties of the sQGP.Comment: 16 pages, 14 figure
Permutation symmetry for the tomographic probability distribution of a system of identical particles
The symmetry properties under permutation of tomograms representing the
states of a system of identical particles are studied. Starting from the action
of the permutation group on the density matrix we define its action on the
tomographic probability distribution. Explicit calculations are performed in
the case of the two-dimensional harmonic oscillator.Comment: 13 pages, latex, no figure
Differences in the Prevalence of Non-Communicable Disease between Slum Dwellers and the General Population in a Large Urban Area in Brazil.
Residents of urban slums are at greater risk for disease than their non-slum dwelling urban counterparts. We sought to contrast the prevalences of selected non-communicable diseases (NCDs) between Brazilian adults living in a slum and the general population of the same city, by comparing the age and sex-standardized prevalences of selected NCDs from a 2010 survey in Pau da Lima, Salvador Brazil, with a 2010 national population-based telephone survey. NCD prevalences in both populations were similar for hypertension (23.6% (95% CI 20.9â»26.4) and 22.9% (21.2â»24.6), respectively) and for dyslipidemia (22.7% (19.8â»25.5) and 21.5% (19.7â»23.4)). Slum residents had higher prevalences of diabetes mellitus (10.1% (7.9â»12.3)) and of overweight/obesity (46.5% (43.1â»49.9)), compared to 5.2% (4.2â»6.1) and 40.6% (38.5â»42.8) of the general population in Salvador. Fourteen percent (14.5% (12.1â»17.0)) of slum residents smoked cigarettes compared to 8.3% (7.1â»9.5) of the general population in Salvador. The national telephone survey underestimated the prevalence of diabetes mellitus, overweight/obesity, and smoking in the slum population, likely in part due to differential sampling inside and outside of slums. Further research and targeted policies are needed to mitigate these inequalities, which could have significant economic and social impacts on slum residents and their communities
Phi Mesons from a Hadronic Fireball
Production of mesons is considered in the course of heavy-ion
collisions at SPS energies. We investigate the possible difference in momentum
distributions of mesons measured via their leptonic () and
hadronic () decays. Rescattering of secondary kaons in the dense hadron
gas together with the influence of in-medium kaon potential can lead to a
relative decrease of a yield observed in the hadronic channel. We
analyze how the in-medium modifications of meson properties affect apparent -
reconstructed momentum distributions of mesons. Quantitative results are
presented for central Pb+Pb collisions at .Comment: style Revtex4,9 pages, 5 figures. submitted to Phys. Rev.
Arrival directions of cosmic rays of E .4 EeV
The anisotropy of cosmic rays observed by the Utah Fly's Eye detector has been studied. Emphasis has been placed on examining distributions of events in galactic coordinates. No statistically significant departure from isotropy has been observed for energies greater than 0.4 EeV (1 EeV = 10 to the 18th power eV). Results of the standard harmonic analysis in right ascension are also presented
Cascaded four-wave mixing in tapered plasmonic nanoantenna
We study theoretically the cascaded four-wave mixing (FWM) in broadband
tapered plasmonic nanoantennas and demonstrate a 300-fold increase in nonlinear
frequency conversion detected in the main lobe of the nanoantenna far-field
pattern. This is achieved by tuning the elements of the nanoantenna to resonate
frequencies involved into the FWM interaction. Our findings have a potentially
broad application in ultrafast nonlinear spectroscopy, sensing, on-chip optical
frequency conversion, nonlinear optical metamaterials and photon sources
Classification of non-Riemannian doubled-yet-gauged spacetime
Assuming covariant fields as the `fundamental' variables,
Double Field Theory can accommodate novel geometries where a Riemannian metric
cannot be defined, even locally. Here we present a complete classification of
such non-Riemannian spacetimes in terms of two non-negative integers,
, . Upon these backgrounds, strings become
chiral and anti-chiral over and directions respectively, while
particles and strings are frozen over the directions. In
particular, we identify as Riemannian manifolds, as
non-relativistic spacetime, as Gomis-Ooguri non-relativistic string,
as ultra-relativistic Carroll geometry, and as Siegel's
chiral string. Combined with a covariant Kaluza-Klein ansatz which we further
spell, leads to Newton-Cartan gravity. Alternative to the conventional
string compactifications on small manifolds, non-Riemannian spacetime such as
, may open a new scheme of the dimensional reduction from ten to
four.Comment: 1+41 pages; v2) Refs added; v3) Published version; v4) Sign error in
(2.51) correcte
Quarkonium momentum distributions in photoproduction and B decay
According to our present understanding many production processes
proceed through a coloured state followed by the emission of soft
particles in the quarkonium rest frame. The kinematic effect of soft particle
emission is usually a higher-order effect in the non-relativistic expansion,
but becomes important near the kinematic endpoint of quarkonium energy
(momentum) distributions. In an intermediate region a systematic resummation of
the non-relativistic expansion leads to the introduction of so-called `shape
functions'. In this paper we provide an implementation of the kinematic effect
of soft gluon emission which is consistent with the non-relativistic shape
function formalism in the region where it is applicable and which models the
extreme endpoint region. We then apply the model to photoproduction of
and production in meson decay. A satisfactory description of
decay data is obtained. For inelastic charmonium photoproduction we conclude
that a sensible comparison of theory with data requires a transverse momentum
cut larger than the currently used 1 GeV.Comment: latex, 45 pages; (v2) some typos corrected, version to appear in PR
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