This article describes theLaser calibration systemof theATLAShadronicTileCalorimeter that has been used during the run 1 of the LHC. First, the stability of the system associated readout electronics is studied. It is found to be stable with variations smaller than 0.6 %. Then, the method developed to compute the calibration constants, to correct for the variations of the gain of the calorimeter photomultipliers, is described. These constants were determined with a statistical uncertainty of 0.3 % and a systematic uncertainty of 0.2 % for the central part of the calorimeter and 0.5 % for the end-caps. Finally, the detection and correction of timing mis-configuration of the Tile Calorimeter using the Laser system are also presented.

We report measurements of the lifetimes of the D, D+, and D,+ (F+) mesons produced in e+e collisions at a center-of-mass energy of 29 GeV. The decay vertex distribution in the processes D ~K rr+, D+~E n+n+, and . D+~Prr+ were made using a vertex chamber installed in the High Resolution Spectrometer at the SLAC storage ring PEP. The measured lifetimes are ~ 0=(4.4+1.0%0.6)X10 ' s, w +=(9.2+,'3+1.6)X10 " s, and r +=(3.1+20+0.5)X10 " s. S In addition the lifetime of the B meson is determined assuming that only the B and not the B decays to a D*+ meson. The B is not directly observed. The lifetime w 0 is estimated indirectly to be (8.2+3 7+2.7) X 10

During the last several decades there have been tremendous advances in the power and the techniques of particle accelerators. In parallel, there have been remarkable advances in the understanding of how charged particle beams interact with themselves and with external environments. The current status of beam dynamics is such that some of the mathematical tools for the collective instabilities, phase-space dilutions and beam cooling methods, nonlinear phenomenon, etc. have become practical design tools for currently operating accelerators. As we contemplate the next generation of large-scale accelerator projects, there are more challenges ahead, both in improving the predictive power of the current calculations as well as in developing new topics. This report is a summary of the discussions of the Beam Dynamics (T5) Working Group at Snowmass on the progress and challenges for the beam dynamics of future accelerators.

E769 has just recorded on tape the interactions of 500 million pions, kaons, and protons. A ˇ Cerenkov counter and a TRD were used to tag beam particle types in both positive and negative 250 GeV/c hadron beams. Thin foil Be, Al, Cu, and W targets were used with a spectrometer including silicon microstrips to look for charm decay vertices. Preliminary results show D 0 → K − π + and D + → K − π + π + mass peaks. As the event reconstruction progresses on numerous parallel microprocessors, we intend to explore the p T , x F , A, and flavor dependence of the production of charmed mesons and baryons. 451 INTRODUCTION Experiment 769 was designed to explore how pions, kaons, and protons produce charmed mesons and baryons. To achieve this goal we modified and upgraded the Tagged Photon Laboratory (TPL) at Fermilab. Previously, this apparatus had been used by E691 [1] to photoproduce and fully reconstruct over 10,000 charmed particles. Silicon microstrip planes are employed to separate the primary vertex in an event from secondary charm decay vertices. We used a fast data acquisition system to record a large quantity of data with a fairly open global E T trigger. We rely on offline vertexing, mass reconstruction, and particle identification to find charm. Production event filtering and reconstruction will soon be ready to start on an ACP [2] microprocessor farm.