R. Bartek

The silicon pixel detector is the innermost component of the CMS tracking system, providing high precision space point measurements of charged particle trajectories.Before 2018 the instantaneous luminosity of the LHC is expected to reach about 2 x 10 34 cm -2 s -1 , which will significantly increase the number of interactions per bunch crossing.To maintain a high tracking efficiency, CMS has planned to replace the current pixel system during phase I by a new lightweight detector, equipped with an additional 4th layer in the barrel, and one additional forward/backward disk.The present status of barrel modules production will be presented, including preliminary results from tests on the first production pixel modules of the new pixel tracker.

The silicon pixel detector is the innermost component of the CMS tracking system, providing high precision space point measurements of charged particle trajectories. Before 2018 the instantaneous luminosity of the LHC is expected to reach about 2 x 10 cm−2s−1, which will significantly increase the number of interactions per bunch crossing. To maintain a high tracking efficiency, CMS has planned to replace the current pixel system during phase I by a new lightweight detector, equipped with an additional 4th layer in the barrel, and one additional forward/backward disk. The present status of barrel modules production will be presented, including preliminary results from tests on the first production pixel modules of the new pixel tracker. Presented at LP2015 XXVII International Symposium on Lepton Photon Interactions at High Energies Current Status of the Pixel Phase I Upgrade in CMS: Barrel Module Production Rachel BARTEK∗ † National Taiwan University (TW) E-mail: rachel.bartek@cern.ch The silicon pixel detector is the innermost component of the CMS tracking system, providing high precision space point measurements of charged particle trajectories. Before 2018 the instantaneous luminosity of the LHC is expected to reach about 2 x 1034 cm−2s−1, which will significantly increase the number of interactions per bunch crossing. To maintain a high tracking efficiency, CMS has planned to replace the current pixel system during phase I by a new lightweight detector, equipped with an additional 4th layer in the barrel, and one additional forward/backward disk. The present status of barrel modules production will be presented, including preliminary results from tests on the first production pixel modules of the new pixel tracker. International Symposium on Lepton Photon Interactions at High Energies 17-22 August 2015 University of Ljubljana, Slovenia ∗Speaker. †on behalf of the CMS Collaboration c © Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0). http://pos.sissa.it/ Barrel Module Production Rachel BARTEK

A search for the standard model Higgs boson is presented in the associated production channel Z(ττ)H(bb) where each tau decays leptonically, one to an electron, the other to a muon and associated neutrinos. A data sample comprising of 5.0 fb-1 and 19 fb-1 from the 2011 and 2012 proton collision running periods at a center of massof 7 and 8 TeV, respectively, has been analyzed and 95% C.L. upper limits derived for Higgs masses of 110-135 GeV.

The Phase 1 upgrade of the CMS pixel detector, installed by the CMS collaboration during the recent extended end-of-year technical stop, is built out of four barrel layers (BPIX) and three forward disks in each endcap (FPIX).It comprises a total of 124M pixel channels, in 1856 modules and it is designed to withstand instantaneous luminosities of up to 2x10 34 cm -2 s -1 with increased detector acceptance and additional redundancy for the tracking, while at the same time reducing the material budget.These goals are achieved using a new readout chip and modified powering and readout schemes, one additional tracking layer both in the barrel and in the disks, and new detector supports including a CO 2 based evaporative cooling system.Different parts of the detector have been assembled over the last year and later brought to CERN for installation inside the CMS tracker.At various stages during the assembly tests have been performed to ensure that the readout and power electronics, and the cooling system meet the design specifications.After tests of the individual components, system tests have been performed before the installation inside CMS.This contribution will review the design and technological choices of the Phase 1 detector, with a focus on the challenges and difficulties encountered, and present results from system tests and from the final commissioning of the detector in-situ using the central CMS DAQ system.