4,858 research outputs found
Remarks on flavour mixings from orbifold compactification
We consider 5d SU(5) GUT models based on the orbifold , and study the different possibilities of placing the SU(5) matter
multiplets in three possible locations, namely, the two branes at the two
orbifold fixed points and SU(5) bulk. We demonstrate that if flavour
hierarchies originate solely from geometrical suppressions due to wavefunction
normalisation of fields propagating in the bulk, then it is not possible to
satisfy even the gross qualitative behaviour of the CKM and MNS matrices
regardless of where we place the matter multiplets.Comment: 4 pages, Late
Density functional theory for fermions close to the unitary regime
We consider interacting Fermi systems close to the unitary regime and compute
the corrections to the energy density that are due to a large scattering length
and a small effective range. Our approach exploits the universality of the
density functional and determines the corrections from the analyical results
for the harmonically trapped two-body system. The corrections due to the finite
scattering length compare well with the result of Monte Carlo simulations. We
also apply our results to symmetric neutron matter.Comment: 4 pages, 2 figure
Model study of hot and dense baryonic matter
The properties of baryonic matter have been investigated at finite density
and temperature using different models. The variation of baryon masses and
fractional number densities with baryon density and temperature obtained from
different models have been compared. The quark hadron phase transition have
been studied using Chiral Colour Dieletric (CCD) model in the quark sector. No
phase transition has been seen for the different variants of the
Zimanyi-Moszkowski model. However, a phase transition is observed for the
linear and non-linear Walecka model.Comment: Latex, 16 postscript figures available on reques
Local and global statistical distances are equivalent on pure states
The statistical distance between pure quantum states is obtained by finding a
measurement that is optimal in a sense defined by Wootters. As such, one may
expect that the statistical distance will turn out to be different if the set
of possible measurements is restricted in some way. It nonetheless turns out
that if the restriction is to local operations and classical communication
(LOCC) on any multipartite system, then the statistical distance is the same as
it is without restriction, being equal to the angle between the states in
Hilbert space.Comment: 5 pages, comments welcom
A comparison of ultraviolet sensitivities in universal, nonuniversal, and split extra dimensional models
We discuss the origin of ultraviolet sensitivity in extra dimensional
theories, and compare and contrast the cutoff dependences in universal,
nonuniversal and split five dimensional models. While the gauge bosons and
scalars are in the five dimensional bulk in all scenarios, the locations of the
fermions are different in different cases. In the universal model all fermions
can travel in the bulk, in the nonuniversal case they are all confined at the
brane, while in the split scenario some are in the bulk and some are in the
brane. A possible cure from such divergences is also discussed.Comment: 9 pages, Latex, no figure, v2: further clarifications and references
added, accepted for publication in Phys. Rev.
Lepton Flavours at the Early LHC Experiments as the Footprints of the Dark Matter Producing Mechanisms
The mSUGRA parameter space corresponding to light sleptons well within the
reach of LHC and relatively light squarks and gluinos (mass 1 TeV) has
three regions consistent with the WMAP data on dark matter relic density and
direct mass bounds from LEP 2. Each region can lead to distinct leptonic
signatures from squark-gluino events during the early LHC experiments
(integrated luminosity or even smaller). In the much studied
stau-LSP coannihilation region with a vanishing common trilinear coupling
() at the GUT scale a large fraction of the final states contain electrons
and / or muons and - - universality holds to a good
approximation. In the not so well studied scenarios with non-vanishing
both LSP pair annihilation and stau-LSP coannihilation could contribute
significantly to the dark matter relic density for even smaller squark-gluino
masses. Our simulations indicate that the corresponding signatures are final
states rich in -leptons while final states with electrons and muons are
suppressed leading to a violation of lepton universality. These features may be
observed to a lesser extent even in the modified parameter space (with non-zero
) where the coannihilation process dominates. We also show that the
generic -leptons + -jets+ signatures without flavour tagging
can also discriminate among the three scenarios. However, the signals become
more informative if the and -jet tagging facilities at the LHC
experiments are utilized.Comment: 28 page
SUSY darkmatter at the LHC - 7 TeV
We have analysed the early LHC signatures of the minimal supergravity
(mSUGRA) model. Our emphasis is on the 7 - run corresponding to an
integrated luminosity of although we have also discussed
briefly the prospects at LHC-10 . We focus on the parameter space yielding
relatively light squark and gluinos consistent with the darkmatter relic
density data and the LEP bounds on the lightest Higgs scalar mass. This
parameter space is only allowed for non-vanishing trilinear soft breaking term
. A significant region of the parameter space with large to moderate
negative values of consistent with the stability of the scalar potential
and relic density production via neutralino annihilation and/or neutralino -
stau coannihilation yields observable signal via the jets + missing transverse
energy channel. The one lepton + jets + missing energy signal is also viable
over a smaller but non-trivial parameter space. The ratio of the size of the
two signals - free from theoretical uncertainties - may distinguish between
different relic density generating mechanisms. With efficient -tagging
facilities at 7 the discriminating power may increase significantly. We
also comment on other dark matter relic density allowed mSUGRA scenarios and
variants there of in the context of LHC-7 .Comment: Brief comments on signals at 7 TeV in the Higgs funnel region of
mSUGRA, models with non universal scalar and gaugino masses have been added.
Accepted for publication in PR
Conformal higher-order viscoelastic fluid mechanics
We present a generally covariant formulation of conformal higher-order
viscoelastic fluid mechanics with strain allowed to take arbitrarily large
values. We give a general prescription to determine the dynamics of a
relativistic viscoelastic fluid in a way consistent with the hypothesis of
local thermodynamic equilibrium and the second law of thermodynamics. We then
elaborately study the transient time scales at which the strain almost relaxes
and becomes proportional to the gradients of velocity. We particularly show
that a conformal second-order fluid with all possible parameters in the
constitutive equations can be obtained without breaking the hypothesis of local
thermodynamic equilibrium, if the conformal fluid is defined as the long time
limit of a conformal second-order viscoelastic system. We also discuss how
local thermodynamic equilibrium could be understood in the context of the
fluid/gravity correspondence.Comment: 26 pages; v2: minor corrections; v3: minor corrections, to appear in
JHE
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