19,590 research outputs found
Towards the quantization of the non-relativistic D2-brane in the Pure Spinor Formalism
An attempt is made to apply the pure spinor formalism to the non-relativistic
IIA D2-brane. The fermionic constraints corresponding to the rescaled fermionic
coordinates are given. Two commuting spinor fields are introduced, each one
corresponding to a fermionic constraint. A BRST charge is constructed via the
ansatz proposed by N. Berkovits. The nilpotency of the BRST charge leads to a
set of constraints for the two spinor fields including pure spinor constraints.
A novel non-trivial solution is given for one of the spinor fields which can be
written as a sum of two pure spinors.Comment: 23 pages in latex, no figures; discussion added, some typos
corrected, more references adde
Top effective operators at the ILC
We investigate the effect of top trilinear operators in t tbar production at
the ILC. We find that the sensitivity to these operators largely surpasses the
one achievable by the LHC either in neutral or charged current processes,
allowing to probe new physics scales up to 4.5 TeV for a centre of mass energy
of 500 GeV. We show how the use of beam polarisation and an eventual energy
upgrade to 1 TeV allow to disentangle all effective operator contributions to
the Ztt and gamma tt vertices.Comment: LaTeX 13 pages. Typos corrected. Final version in JHE
Top effective operators at the ILC
We investigate the effect of top trilinear operators in t tbar production at
the ILC. We find that the sensitivity to these operators largely surpasses the
one achievable by the LHC either in neutral or charged current processes,
allowing to probe new physics scales up to 4.5 TeV for a centre of mass energy
of 500 GeV. We show how the use of beam polarisation and an eventual energy
upgrade to 1 TeV allow to disentangle all effective operator contributions to
the Ztt and gamma tt vertices.Comment: LaTeX 13 pages. Typos corrected. Final version in JHE
Shedding light on the asymmetry: the photon handle
We investigate a charge asymmetry in production at the LHC
that provides complementary information to the measured asymmetries in production. We estimate the experimental uncertainty in its measurement at
the LHC with 8 and 14 TeV. For new physics models that simultaneously reproduce
the asymmetry excess in at the Tevatron and the SM-like asymmetry at
the LHC, the measurement in at the LHC could exhibit
significant deviations with respect to the SM prediction.Comment: LaTeX 15 page
Free energy and vibrational entropy difference between ordered and disordered Ni3Al
We have calculated free energy and vibrational entropy differences in Ni3Al between its equilibrium ordered structure and a disordered fcc solid solution. The free energy and entropy differences were calculated using the method of adiabatic switching in a molecular-dynamics formalism. The path chosen for the free-energy calculations directly connects the disordered with the ordered state. The atomic interactions are described by embedded-atom-method potentials. We find that the vibrational entropy difference increases with temperature from 0.14kB/atom at 300 K to 0.22kB/atom at 1200 K. We have calculated the density of states (DOS) of the disordered phase from the Fourier transform of the velocity-velocity autocorrelation function. The disordered DOS looks more like a broadened version of the ordered DOS. Analysis of the partial density of states shows that the Al atoms vibrations are most affected by the compositional disorder. The phonon partial spectral intensities along the 〈100〉 direction show that the vibrational spectrum of the disordered phase contains intensities at optical mode frequencies of the ordered alloy. We find that the volume difference between the ordered and disordered phases plays the most crucial role in the magnitude of the vibrational entropy difference. If the lattice constant of the two phases is set to the same value, the vibrational entropy difference decreases to zero
Constraints on Mass Spectrum of Fourth Generation Fermions and Higgs Bosons
We reanalyze constraints on the mass spectrum of the chiral fourth generation
fermions and the Higgs bosons for the standard model (SM4) and the two Higgs
doublet model (THDM). We find that the Higgs mass in the SM4 should be larger
than roughly the fourth generation up-type quark mass, while the light CP even
Higgs mass in the THDM can be smaller. Various mass spectra of the fourth
generation fermions and the Higgs bosons are allowed. The phenomenology of the
fourth generation models is still rich.Comment: 15 pages, 16 figures; some points clarified, references added, to
appear in Phys.Rev.
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