This presentation reviews the initial commissioning and operation of the CMS experiment with beams at the LHC starting with the first collisions at 7TeV on March 30, 2010. The initial experience with ...operating the detector and commissioning of the trigger is described. A few issues that have come up in this initial period of operation are described. Emphasis is put on experience with the CMS electronics.
The High Luminosity LHC (HL-LHC) will deliver luminosities of up to 5 x 10 super(34) Hz/cm super(2), with an average of about 140 overlapping proton-proton collisions per bunch crossing. These ...extreme pileup conditions place stringent requirements on the trigger system to be able to cope with the resulting event rates. A key component of the CMS upgrade for HL-LHC is a track trigger system which would identify tracks with transverse momentum above 2 GeV/c already at the first-level trigger. This paper presents the status of proposals for implementing the L1 tracking in conjunction with the planned upgrade for the silicon tracker of the CMS experiment.
The high instantaneous luminosities expected following the upgrade of the Large Hadron Collider (LHC) to the High-Luminosity LHC (HL-LHC) pose major experimental challenges for the CMS experiment. A ...central component to allow efficient operation under these conditions is the reconstruction of charged particle trajectories and their inclusion in the hardware-based trigger system. There are many challenges involved in achieving this: a large input data rate of about 20–40 Tb/s processing a new batch of input data every 25 ns, each consisting of about 15,000 precise position measurements and rough transverse momentum measurements of particles (“stubs”); performing the pattern recognition on these stubs to find the trajectories; and producing the list of trajectory parameters within 4 μs. This paper describes a proposed solution to this problem, specifically, it presents a novel approach to pattern recognition and charged particle trajectory reconstruction using an all-FPGA solution. The results of an end-to-end demonstrator system, based on Xilinx Virtex-7 FPGAs, that meets timing and performance requirements are presented along with a further improved, optimized version of the algorithm together with its corresponding expected performance.
We present an electronics design for a tracking trigger for the CERN SLHC. The on detector part uses asynchronous logic so the only clock required is the LHC crossing clock. High Pt tracks are ...identified with a hierarchical method that finds track stubs using closely spaced pairs of detectors. Track segments (called tracklets) are then formed from pairs of stubs that are separated by 40 mm. This separation is close enough so that matching stubs is relatively easy but far enough apart so that the tracklets can be projected to another layer with mm accuracy. Matching segments in two or more layers then define a track.
Since the discovery of charm mesons in 1974 precision measurements of their decay in fixed target and colliding beam experiments at particle accelerators have yielded a wealth of information on the ...weak and strong interactions of heavy flavor quarks. This review summarizes what is presently known experimentally and theoretically in the field and provides an excellent foundation for future charm studies at the LHC and the next generation of e super(+)e super(-) colliders.
Status of CMS Ryd, A.
Nuclear physics. Section B, Proceedings supplement,
06/2011, Letnik:
215, Številka:
1
Journal Article
This presentation reviews the initial commissioning and operation of the CMS experiment with beams at the LHC starting with the first collisions on March 30, 2010 at 7 TeV. The initial experience ...with operating the detector and commissioning of the the trigger is described. A few issues that have come up in this initial period of operation are described.
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