218 research outputs found
Unusual Charged Higgs Signals at LEP-2
We have made a detailed study of the signals produced at LEP-2 from charged
scalar bosons whose dominant decay channels are into four fermions. The event
rates as well as kinematics of the final states are discussed when such scalars
are either pair-produced or are generated through a tree-level interaction
involving a charged scalar, the W and the Z. The backgrounds in both cases are
discussed. We also suggest the possibility of reconstructing the mass of such a
scalar at LEP-2.Comment: 12 pages, LateX, 9 Postscript figures, uses eps
Probing Gauge-Mediated Supersymmetry Breaking Through Polarized Electron Beams in an Collider
Using the facts that in Gauge-Mediated Supersymmetry Breaking schemes, masses
of the right and the left sfermions can differ widely, and the gravitino is the
Lightest Supersymmetric Particle, we show that it is possible to obtain
unambiguous signatures of such schemes in a high energy collider if
one looks at the asymmetries in the cross-sections for certain final states
with left-and right-polarized beams.Comment: Plain LaTeX file, with four postscript figures adde
Tevatron Mass Limits for Heavy Quarks Decaying via Flavor Changing Neutral Current
The dimuon and dielectron data from the Tevatron collider are used
to probe for heavy quarks, which decay dominantly via flavour changing neutral
current. Depending on whether the decay occurs at the tree or loop
level, one gets a lower mass limit of 85 or 75 GeV. The former applies to
singlet, vector doublet and mirror type quarks while the latter applies to a
lefthanded quark doublet of the fourth generation.Comment: 13 pages, TIFR/TH/92-58, Two figures to be supplied on reques
Radiative decay of the lightest neutralino in an R-parity violating supersymmetric theory
In an R-parity violating supersymmetric scenario, the lightest neutralino
is no longer a stable particle. We calculate the branching
ratio for the decay mode which
occurs at the one-loop level. Taking into account bilinear as well as trilinear
lepton number violating interactions as the sources of R-parity violation, we
make a detailed scan of the parameter space, both with and without gaugino mass
unification and including the constraints on the neutrino sector from the
recent Superkamiokande results. This study enables one to suggest interesting
experimental signals distinguishing between the two types of R-parity breaking,
and also to ascertain whether such radiative decays can give rise to collider
signals of the type + from pair-produced
neutralinos.Comment: 25 pages, LaTex including postscript figures. Uses axodraw.sty. Minor
typographic errors correcte
New scalar resonances from sneutrino-Higgs mixing in supersymmetry with small lepton number (R-parity) violation
We consider new s-channel scalar exchanges in top quark and massive
gauge-bosons pair production in e+e- collisions, in supersymmetry with a small
lepton number violation. We show that a soft bilinear lepton number violating
term in the scalar potential which mixes the Higgs and the slepton fields can
give rise to a significant scalar resonance enhancement in e+e- -> ZZ, W+W- and
in e+e- -> t t(bar). The sneutrino-Higgs mixed state couples to the incoming
light leptons through its sneutrino component and to either the top quark or
the massive gauge bosons through its Higgs component. Such a scalar resonance
in these specific production channels cannot result from trilinear Yukawa-like
R-parity violation alone, and may, therefore, stand as strong evidence for the
existence of R-parity violating bilinears in the supersymmetric scalar
potential. We use the LEP2 measurements of the WW and ZZ cross-sections to
place useful constrains on this scenario, and investigate the expectations for
the sensitivity of a future linear collider to these signals. We find that
signals of these scalar resonances, in particular in top-pair production, are
well within the reach of linear colliders in the small lepton number violation
scenario.Comment: 22 pages in revtex, 10 figures embadded in the text using epsfi
Two-Loop Neutrino Masses and the Solar Neutrino Problem
The addition of singlet right-handed neutrinos to the Standard Model
leads to radiatively generated mass corrections for the doublet
neutrinos. For those neutrinos which are massless at the tree level after this
addition, this implies a small mass generated at the two-loop level via
exchange. We calculate these mass corrections exactly by obtaining an
analytic form for the general case of doublets and singlets. As a
phenomenological application, we consider the case and examine the masses
and mixings of the doublet neutrinos which arise as a result of the two-loop
correction in the light of experimental data from two sources which may shed
light on the question of neutrino masses. These are(a) the neutrino detectors
reporting a solar neutrino deficit (and its resolution via
Mikheyev-Smirnov-Wolfenstein matter oscillations), and
(b) the COBE satellite data on the non-zero angular variations of the cosmic
microwave background temperature (and its possible implications for hot dark
matter). Within the framework of the extension considered here, which leaves
the gauge group structure of the Standard Model intact, we show that it is
possible for neutrinos to acquire small masses naturally, with values which are
compatible with current theoretical bias and experimental data.Comment: 24 pages, Two figures, attached as postscript files at the end,
Latex, CTP-TAMU-76/93, MRI-PHY-12/93, LTH-32
‘I arranged my own marriage': arranged marriages and post-colonial feminism
This article looks at the practice of arranged marriage among women of Indian, Pakistani and Bangladeshi origin resident in Britain. It examines the conflation of arranged marriages with forced marriages and the assumption that arranged marriages are examples of cultural practices that thwart individual agency. Drawing upon original empirical data, this article will argue that in the practice of arranged marriage, some South Asian women are able to exercise agency while choosing their marriage partner. They adapt traditional arranged marriage practices to navigate their way around strict cultural expectations and to negotiate with their family members the choice of a match that is favourable for them. It provides a corrective account of arranged marriages by challenging the stereotype of the ‘oppressed third world women' and their experiences of such marriages. The article will do this by employing the idea of post-colonial feminism and by highlighting two long-standing issues in feminist debates: the idea of agency and the conception and role of power in the struggle for women's rights. It will make a case for a post-colonial approach to feminism as one way of reconciling feminism with the politics of multiculturalism
A clean signal for a top-like isosinglet fermion at the Large Hadron Collider
We predict a clean signal at the Large Hadron Collider (=14 TeV for
a scenario where there is a top-like, charge +2/3 vectorlike isosinglet
fermion. Such a quark, via mixing with the standard model top, can undergo
decays via both flavour-changing Z-boson coupling and flavour-changing Yukawa
interactions. We concentrate on the latter channel, and study the situation
where, following its pair-production, the heavy quark pair gives rise to two
tops and two Higgs boson. We show that the case where each Higgs decays in the
channel, there can be a rather distinct and background-free signal
that can unveil the existence of the vectorlike isosinglet quark of this kind.Comment: 14 pages, 5 figures, 4 table
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