3,107 research outputs found
Measuring CMB polarisation with the Planck HFI
We describe the Planck HFI design and expected performances for measuring CMB
polarisation.Comment: Proceedings of the Pol2001 "Astrophysical Polarised Backgrounds"
conference, Bologna, 9-12 october 200
Evidence for non-exponential elastic proton-proton differential cross-section at low |t| and sqrt(s) = 8 TeV by TOTEM
The TOTEM experiment has made a precise measurement of the elastic
proton-proton differential cross-section at the centre-of-mass energy sqrt(s) =
8 TeV based on a high-statistics data sample obtained with the beta* = 90
optics. Both the statistical and systematic uncertainties remain below 1%,
except for the t-independent contribution from the overall normalisation. This
unprecedented precision allows to exclude a purely exponential differential
cross-section in the range of four-momentum transfer squared 0.027 < |t| < 0.2
GeV^2 with a significance greater than 7 sigma. Two extended parametrisations,
with quadratic and cubic polynomials in the exponent, are shown to be well
compatible with the data. Using them for the differential cross-section
extrapolation to t = 0, and further applying the optical theorem, yields total
cross-section estimates of (101.5 +- 2.1) mb and (101.9 +- 2.1) mb,
respectively, in agreement with previous TOTEM measurements.Comment: Final version published in Nuclear Physics
Pinning down neutrino oscillation parameters in the 2-3 sector with a mgnetised atmospheric neutrino detector: a new study
We determine the sensitivity to neutrino oscillation parameters from a study
of atmospheric neutrinos in a magnetised detector such as the ICAL at the
proposed India-based Neutrino Observatory. In such a detector that can {\em
separately} count and -induced events, the
relatively smaller (about 5\%) uncertainties on the neutrino--anti-neutrino
flux ratios translate to a constraint in the analysis that results in
a significant improvement in the precision with which neutrino oscillation
parameters such as can be determined. Such an effect is
unique to all magnetisable detectors and constitutes a great advantage in
determining neutrino oscillation parameters using such detectors. Such a study
has been performed for the first time here. Along with an increase in the
kinematic range compared to earlier analyses, this results in sensitivities to
oscillation parameters in the 2--3 sector that are comparable to or better than
those from accelerator experiments where the fluxes are significantly higher.
For example, the precisions on and
achievable for 500 kTon yr exposure of ICAL are
and respectively for both normal and inverted
hierarchies. The mass hierarchy sensitivity achievable with this combination
when the true hierarchy is normal (inverted) for the same exposure is
()
Top Partner Discovery in the channel at the LHC
In this paper we study the discovery potential of the LHC run II for heavy
vector-like top quarks in the decay channel to a top and a boson. Despite
the usually smaller branching ratio compared to charged-current decays, this
channel is rather clean and allows for a complete mass reconstruction of the
heavy top. The latter is achieved in the leptonic decay channel of the
boson and in the fully hadronic top channel using boosted jet and jet
substructure techniques. To be as model-independent as possible, a simplified
model approach with only two free parameters has been applied. The results are
presented in terms of parameter space regions for evidence or
discovery for such new states in that channel.Comment: 24 pages, 8 figures, version 2 updated to JHEP 01 (2015) 08
Search for Neutral Higgs Bosons of the Minimal Supersymmetric Standard Model in e+e- Interactions at root(s)=192-202GeV
A search for the lightest neutral CP-even and the neutral CP-odd Higgs bosons
of the Minimal Supersymmetric Standard Model is performed using 233.2 pb-1 of
integrated luminosity collected with the L3 detector at LEP at centre-of-mass
energies 192-202 GeV. No signal is observed and lower mass limits are given as
a function of tan(beta) for two scalar top mixing hypotheses. For tan(beta)
greater than 0.8, they are mh > 83.4 GeV and mA > 83.8 GeV at 95 % confidence
level
Heavy Flavour Results at the LHC
We present a brief overview of the first flavour physics results at the LHC.
Cross-section for charm and beauty production have been measured by several
experiments and the first competitive results on D and B decays are presented.Comment: Proceedings of the XXXI Physics in Collision Conference, Vancouver,
Canada, August 28 - September 1, 201
Prospects for the direct detection of neutralino dark matter in orbifold scenarios
We analyse the phenomenology of orbifold scenarios from the heterotic
superstring, and the resulting theoretical predictions for the direct detection
of neutralino dark matter. In particular, we study the parameter space of these
constructions, computing the low-energy spectrum and taking into account the
most recent experimental and astrophysical constraints, as well as imposing the
absence of dangerous charge and colour breaking minima. In the remaining
allowed regions the spin-independent part of the neutralino-proton cross
section is calculated and compared with the sensitivity of dark matter
detectors. In addition to the usual non universalities of the soft terms in
orbifold scenarios due to the modular weight dependence, we also consider
D-term contributions to scalar masses. These are generated by the presence of
an anomalous U(1), providing more flexibility in the resulting soft terms, and
are crucial in order to avoid charge and colour breaking minima. Thanks to the
D-term contribution, large neutralino detection cross sections can be found,
within the reach of projected dark matter detectors.Comment: 51 pages, 25 figure
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