We analyze the correlation of QCD one-loop effects on the partial widths of the three neutral Higgs bosons of the MSSM decaying into quark-antiquark pairs. The SUSY-QCD effects turn out to be ...comparable or even larger than the standard QCD effects and are slowly decoupling in a wide window of the parameter space. Our study is aimed at elucidating the possible supersymmetric nature of the neutral Higgs bosons that might be discovered in the near future at the Tevatron and/or at the LHC. In particular, we point out the presence of potentially large SUSY corrections to the various neutral Higgs production cross-sections.
Phys.Lett.B425:329-336,1998 Observing a heavy charged Higgs boson produced in the near future at the
Tevatron or at the LHC would be instant evidence of physics beyond the Standard
Model. Whether ...such a Higgs boson would be supersymmetric or not it could only
be decided after accurate prediction of its properties. Here we compute the
decay width of the dominant decay of such a boson, namely H^+ -> t \bar{b},
including the leading electroweak corrections originating from large Yukawa
couplings within the MSSM. These electroweak effects turn out to be of
comparable size to the O(alpha_s) QCD corrections in relevant portions of the
MSSM parameter space. Our analysis incorporates the stringent low-energy
constraints imposed by radiative B-meson decays.
The MAGIC collaboration has studied the high peaked BL-Lac object 1ES1218+30.4 at a redshift z = 0.182, using the MAGIC imaging air Cherenkov telescope located on the Canary island of La Palma. A ...gamma-ray signal was observed with 6.4sigma significance. The differential energy spectrum for an energy threshold of 120GeV can be fitted by a simple power law yielding F_E(E) = (8.1+-2.1)*10^-7 (E/250GeV)^(-3.0+-0.4) TeV^-1 m^-2 s^-1. During the six days of observation in January 2005 no time variability on time scales of days was found within the statistical errors. The observed integral flux above 350GeV is nearly a factor two below the the upper limit reported by the Whipple Collaboration in 2003.
Eur.Phys.J.C2:373-392,1998 We analyze the one-loop effects (strong and electroweak) on the
unconventional top quark decay mode $t\rightarrow H^{+} b$ within the MSSM. The
results are presented in the ...on-shell renormalization scheme with a physically
well motivated definition of $\tan\beta$. The study of this process at the
quantum level is useful to unravel the potential supersymmetric nature of the
charged Higgs emerging from that decay. As compared with the standard mode
$t\rightarrow W^{+} b$, the corrections to $t\rightarrow H^{+} b$ are large,
slowly decoupling and persist at a sizeable level even for all sparticle masses
well above the LEP 200 discovery range. As a matter of fact, the potential size
of the SUSY effects, which amount to corrections of several ten percent, could
counterbalance the standard QCD corrections and even make them to appear with
the ``wrong'' sign. Therefore, if the charged Higgs decay of the top quark is
kinematically allowed -a possibility which is not excluded by the recent
measurements of the branching ratio $BR(t\rightarrow W^{+} b)$ at the Tevatron
- it could be an invaluable laboratory to search for ``virtual'' supersymmetry.
While a first significant test of these effects could possibly be performed at
the upgraded Tevatron, a more precise verification would most likely be carried
out in future experiments at the LHC.
The long-duration GRB050713a was observed by the MAGIC Telescope, 40 seconds after the burst onset, and followed up for 37 minutes, until twilight. The observation, triggered by a SWIFT alert, ...covered energies above ~175 GeV. Using standard MAGIC analysis, no evidence for a gamma signal was found. As the redshift of the GRB was not measured directly, the flux upper limit, estimated by MAGIC, is still compatible with the assumption of an unbroken power-law spectrum extending from a few hundred keV to our energy range.
Astrophys.J.641:L9-L12,2006 The long-duration GRB050713a was observed by the MAGIC Telescope, 40 seconds
after the burst onset, and followed up for 37 minutes, until twilight. The
observation, ...triggered by a SWIFT alert, covered energies above ~175 GeV. Using
standard MAGIC analysis, no evidence for a gamma signal was found. As the
redshift of the GRB was not measured directly, the flux upper limit, estimated
by MAGIC, is still compatible with the assumption of an unbroken power-law
spectrum extending from a few hundred keV to our energy range.
