477 research outputs found
Invisible Decays of the Supersymmetric Higgs and Dark Matter
We discuss effects of the light sparticles on decays of the lightest Higgs in
a supersymmetric model with nonuniversal gaugino masses at the high scale,
focusing on the `invisible' decays into neutralinos. These can impact
significanlty the discovery possibilities of the lightest Higgs at the LHC. We
show that due to these decays, there exist regions of the space where
the B.R. becomes dangerously low even after imposing
the LEP constraints on the sparticle masses, implying a possible preclusion of
its discovery in the channel. We find that there exist regions
in the parameter space with acceptable relic density and where the ratio falls
below 0.6, implying loss of signal in the channel. These
regions correspond to masses which should be
accessible already at the Tevatron. Further we find that considerations of
relic density put lower limit on the U(1) gaugino mass parameter
independently of and .Comment: 17 pages, 11 figures, Talk presented at Appi2002, Accelerator and
Particle Physics Institute, Appi, Iwate, Japan, February 13--16 200
New Physics with three-photon events at LEP
The effect of the most general \z3gt vertex in the reaction e^+e^- \ra
3\gamma is studied with a particular attention to LEP searches. We give exact
analytical expressions including realistic cuts for the signal and present a
detailed analysis based on a Monte Carlo that includes the effect of the
irreducible QED cross section. As special applications we discuss the
effect of heavy scalars, fermions and gauge bosons and comment on the
``monopole" connection.Comment: No changes made from previous version, 34 pages, LateX, uses epsf, 11
.eps figs., full paper (including figs) is also available via WWW at
http://lapphp0.in2p3.fr/preplapp/psth/lastee3g.ps.gz or via anonymous ftp at
ftp:///lapphp0.in2p3.fr/pub/preprints-theorie/ftpee3g.u
Minimal Ten-parameter Hermitian Texture Zeroes Mass Matrices and the CKM Matrix
Hermitian mass matrices for the up and down quarks with texture zeroes but
with the minimum number of parameters, ten, are investigated. We show how these
{\em minimum parameter} forms can be obtained from a general set of hermitian
matrices through weak basis transformations. For the most simple forms we show
that one can derive exact and compact parametrizations of the CKM mixing matrix
in terms of the elements of these mass matrices (and the quark masses).Comment: 14 pages.Talk given by M.B. at the MRST 98, ``Towards the Theory of
Everything", Montr\'eal, 13-15 May 199
Lab-frame observables for probing the top-Higgs interaction
We investigate methods to explore the CP nature of the coupling
at the LHC, focusing on associated production of the Higgs with a
pair. We first discuss the constraints implied by low-energy observables and by
the Higgs-rate information from available LHC data, emphasizing that they
cannot provide conclusive evidence on the nature of this coupling. We then
investigate kinematic observables that could probe the coupling
directly, in particular quantities that can be constructed out of just
lab-frame kinematics. We define one such observable by exploiting the fact that
spin correlations do also carry information about the CP-nature of
the coupling. Finally, we introduce a CP-odd quantity and a
related asymmetry, able to probe CP violation in the coupling and
likewise constructed out of lab-frame momenta only.Comment: 32 pages, updated with latest data from ATLAS and references adde
NLO corrections to WWZ and ZZZ production at the ILC
We calculate the full one-loop electroweak corrections to tri-boson
production (ZZZ and WWZ) at the ILC. This is important to understand the
Standard Model (SM) gauge quartic couplings which can be a window on the
mechanism of spontaneous symmetry breaking. We find that even after subtracting
the leading QED corrections, the electroweak corrections can still be large
especially as the energy increases.Comment: 7 pages, proceedings of the 3rd CPP Workshop, September 23-25, 2010,
KEK Tsukuba Japa
Single production of excited electrons at future e^-e^+, ep and pp colliders
We analyzed the potential of the LC with TeV, LCLHC
based ep collider with TeV and LHC with TeV to
search for excited electrons through transition magnetic type couplings with
gauge bosons. The signal and corresponding backgrounds
are studied in detail.Comment: 11 pages, 11 figures, 3 table
Excited Leptons at the CERN Large Hadron Collider
We analyze the potential of the CERN Large Hadron Collider (LHC) to search
for excited spin-1/2 electrons and neutrinos. Assuming a SU(2)_L X U(1)_Y
invariant model, we study in detail the single production of excited electrons
and neutrinos and respective backgrounds through the reactions p p -> e+ e- V
and e+- \nu V with V=photon, W, or Z. We show that the LHC will be able to
tighten considerably the direct constraints on these possible new states,
probing excited lepton masses up to 1-2 TeV depending on their couplings to
fermions and gauge bosons.Comment: 15 pages, 7 figure
Physics at the Linear Collider
The physics at the planned colliders is discussed around three main
topics corresponding to different manifestations of symmetry breaking:
physics in the no Higgs scenario, studies of the properties of the Higgs and
precision tests of SUSY. A comparison with the LHC is made for all these cases.
The mode of the linear collider will also be reviewed.Comment: 31 pages, 12 figures. Invited talk given at the Fifth Workshop on
High Energy Physics Phenomenology, Inter-University Centre for Astronomy and
Astrophysics, Pune, India, January 12 - 26, 199
Semi-leptonic four-fermion final states in polarised \gamma\gamma reactions: Exact results vs an improved narrow width approximation
We calculate the process with the full set of Feynman diagrams. We consider different
implementations of the width and different combinations of the photon
polarisations. The results of an improved narrow width approximation based on
with full spin-correlations that takes into
account different angular cuts as well as cuts on the invariant masses are
compared to those of the complete calculation.Comment: paper in LATEX, 19 pages, 3 figures. Complete psfile available via
anonymous ftp at ftp://lapphp0.in2p3.fr/pub/preprints-theorie/enslapp635.uu
or at http://lapphp0.in2p3.fr/preplapp/psth/enslapp635.ps.g
Biliary cirrhosis and sepsis are two risk factors of failure after surgical repair of major bile duct injury post-laparoscopic cholecystectomy.
International audienceBACKGROUND: Major bile duct injury (MBDI) remains frequent after laparoscopic cholecystectomy (LC) reaching 0.3 to 0.6 % and is associated with a significant mortality rate. The aim of this study was to retrospectively analyze the factors likely to influence the long-term results of surgical repair for MBDI occurring after LC. METHODS: Medical records of patients referred to our referral center from January 1992 to January 2010 for management of bile duct injury following LC were retrospectively analyzed, and patients with MBDI were identified. Clinicopathological factors likely to influence long-term results after surgical repair were assessed by univariate and multivariable analysis. RESULTS: During the study period, 38 patients were treated for MBDI. These 38 patients underwent Roux-en-Y hepaticojejunostomy (HJ) or HJ revision in 25 (66 %) and 13 (34 %) cases, respectively. The median follow-up period was 93 (26-204) months. A Clavien-Dindo post-operative morbidity class >3 occurred in 10 (26 %) cases and was independently associated with a surgical repair performed during a sepsis period (OR = 102.5; IC 95 % [7.12; 11,352], p < 0.007). Long-term results showed that biliary strictures occurred in 5 (13 %) cases and were associated with sepsis (p < 0.006), liver cirrhosis (p < 0.002) and post-operative complications (p < 0.012). Multivariate analysis revealed that only liver cirrhosis remained predictive of stricture (OR = 26.4, 95 % CI [2; 1,018], p < 0.026). CONCLUSION: When MBDI occurs following LC, HJ seems to be the optimal treatment but should not be performed during a sepsis period. Long-term results are significantly altered by the presence of a biliary cirrhosis at time of repair
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