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We describe the most recent results from the TOTEM collaboration at the LHC, namely the elastic cross section measurements at a center-of-mass on 2.76, 7, 8 and 13 TeV. No structure or resonance is observed at high $t$ at high center-of-mass energies. A pure exponential form of $d sigma/dt$ is excluded both at 8 and 13 TeV. Accessing the very low $t$ region allows measuring the $rho$ parameter at 13 TeV.
We present first results from the ATLAS Zero Degree Calorimeters (ZDC) based on 7~TeV pp collision data recorded in 2010. The ZDC coverage of +/-~350 microradians about the forward direction makes possible the measurement of neutral particles (primarily pi0s and neutrons) over the kinematic region x_F >~0.1 and out to p_T<~ 1.2 GeV/c at large x_F. The ATLAS ZDC is unique in that it provides a complete image of both electromagnetic and hadronic showers.This is illustrated with the reconstruction of pi0s with energies of 0.7-3.5 TeV. We also discuss the waveform reconstruction algorithm which has allowed good time-of-flight resolution on leading neutrons emerging from the collisions despite the sparse (40 MHz) sampling of the calorimeter signals used.
The TOTEM experiment with its detectors in the forward region of CMS and the Roman Pots along the beam line will determine the total pp cross-section via the optical theorem by measuring both the elastic cross-section and the total inelastic rate. TOTEM will have dedicated runs with special high-beta* beam optics and a reduced number of proton bunches resulting in a low effective luminosity between 1.6 x 10^{28} cm^{-2} s^{-1} and 2.4 x 10^{29} cm^{-2} s^{-1}. In these special conditions also an absolute luminosity measurement will be made, allowing the calibration of the CMS luminosity monitors needed at higher luminosities. The acceptance of more than 90 % of all leading protons in the Roman Pot system, together with CMSs central and TOTEMs forward detectors extending to a maximum rapidity of 6.5, makes the combined CMS+TOTEM experiment a unique instrument for exploring diffractive processes. Scenarios for running at higher luminosities necessary for hard diffractive phenomena with low cross-sections are under study.
We present an overview of recent results from the CP-PACS computer on the quenched light hadron spectrum and an on-going two-flavour full QCD study. We find that our quenched hadron mass results are compatible with the mass formulae predicted by quenched chiral perturbation theory, which we adopt in our final analysis. Quenched hadron masses in the continuum limit show unambiguous and systematic deviations from experiment. For our two-flavour full QCD simulation we present preliminary results on the light hadron spectrum, quark masses and the static potential. The question of dynamical sea quark effects in these quantities is discussed.
The first physics results from the TOTEM experiment are here reported, concerning the measurements of the total, differential elastic, elastic and inelastic pp cross-section at the LHC energy of $sqrt{s}$ = 7 TeV, obtained using the luminosity measurement from CMS. A preliminary measurement of the forward charged particle $eta$ distribution is also shown.
A decade after the discovery of TeV gamma-rays from the blazar Mrk 421 (Punch et al. 1992), the list of TeV blazars has increased to five BL Lac objects: Mrk 421 (Punch et al. 1992; Petry et al. 1996; Piron et al. 2001), Mrk 501 (Quinn et al. 1996; Aharonian et al. 1999; Djannati-Atai et al. 1999), 1ES2344+514 (Catanese et al. 1998), H1426+428 (Horan et al. 2000, 2002; Aharonian et al. 2002; Djannati-Atai et al. 2002) and 1ES1959+650 (Nishiyama et al. 1999; Konopelko et al. 2002; Holder et al. 2002). In this paper we report results from recent observations of Mrk 421, H1426+428 and 1ES1959+650 using the Whipple Observatory 10 m telescope.