7,042 research outputs found
Displaced Higgs production in type III seesaw
We point out that the type III seesaw mechanism introducing fermion triplets
predicts peculiar Higgs boson signatures of displaced vertices with two b jets
and one or two charged particles which can be cleanly identified. In a
supersymmetric theory, the scalar partner of the fermion triplet contains a
neutral dark matter candidate which is almost degenerate with its charged
components. A Higgs boson can be produced together with such a dark matter
triplet in the cascade decay chain of a strongly produced squark or gluino.
When the next lightest supersymmetric particle (NLSP) is bino/wino-like, there
appears a Higgs boson associated with two charged tracks of a charged lepton
and a heavy charged scalar at a displacement larger than about 1 mm. The
corresponding production cross-section is about 0.5 fb for the squark/gluino
mass of 1 TeV. In the case of the stau NLSP, it decays mainly to a Higgs boson
and a heavy charged scalar whose decay length is larger than 0.1 mm for the
stau NLSP mixing with the left-handed stau smaller than 0.3. As this process
can have a large cascade production pb for the squark/gluino mass
TeV, one may be able to probe it at the early stage of the LHC
experiment.Comment: 10 pages, 5 figure
"Soft X-ray transient" outbursts which aren't soft
We have accumulated multiwavelength (X-ray, optical, radio) lightcurves for
the eight black hole X-ray binaries which have been observed to enter a
supposed `soft X-ray transient' outburst, but remained in the low/hard state
throughout the outburst. Comparison of the lightcurve morphologies, spectral
behaviour, properties of the quasi-periodic oscillations and the radio jet
provides the first study of such objects as a sub-class of X-ray transients.
However rather than assuming that these hard state X-ray transients are
different from the `canonical' soft X-ray transient, we prefer to consider the
possibility that new analysis of both soft and hard state X-ray transients in a
spectral context will provide a model capable of explaining the outburst
mechanisms of (almost) all black hole X-ray binaries.Comment: Accepted for publication in New Astronom
The Hard Truth about Some "Soft" X-ray Transients
We have accumulated multiwavelength lightcurves for eight black hole X-ray
binaries which have been observed to enter a supposed ``soft X-ray transient''
outburst, but which in fact remained in the low/hard state throughout the
outburst. Comparison of the lightcurve morphologies, spectral behaviour,
properties of the QPOs and the radio jet provides the first study of such
objects as a subclass of X-ray transients (XRTs). However, rather than assuming
that these hard state XRTs are different from ``canonical'' soft XRTs, we
prefer to consider the possibility that a new analysis of both soft and hard
state XRTs in a spectral context will provide a model capable of explaining the
outburst mechanisms for the majority of black hole X-ray binaries.Comment: 3 pages, 2 figures; to appear in the Proceedings of the 4th
Microquasar Workshop, 2002, eds. Durouchoux, Fuchs & Rodriguez, published by
the Center for Space Physics: Kolkat
Spectroscopic Identification of the Infrared Counterpart to GX5-1
Using CGS4 on UKIRT, we have obtained a 1.95-2.45 micron infrared spectrum of
the primary candidate counterpart to the bright Z LMXB GX5-1. IR photometry by
Naylor, Charles, & Longmore (1992) and the astrometry of Jonker et al. (2000)
had previously identified this star as the most likely counterpart to GX5-1.
The spectrum presented here clearly shows Brackett gamma and He lines in
emission, for the first time confirming the identity of the counterpart.
Similar to our previous spectroscopy of the Z source LMXBs Sco X-1 and Sco X-2
(Bandyopadhyay et al. 1999), the K-band spectrum of GX5-1 shows emission lines
only. We briefly discuss the implications of this spectrum for the nature of
the Z sources.Comment: accepted for publication as a Letter in MNRA
Pairing in High Temperature Superconductors and Berry Phase
The topological approach to the understanding of pairing mechanism in high
superconductors analyses the relevance of the Berry phase factor in this
context. This also gives the evidence for the pairing mechanism to be of
magnetic origin.Comment: 6 page
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