Astrophys.J.642:L119-L122,2006 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.
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.
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.
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 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.
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.
Provider: - Institution: - Data provided by Europeana Collections- Reclams. - juillet 1936 - N°10 (40e Année)- All metadata published by Europeana are available free of restriction under the Creative ...Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
