# CERN Preprints

2015-09-04
15:37
 First measurement of the differential branching fraction and $C\!P$ asymmetry of the $B^\pm\to\pi^\pm\mu^+\mu^-$ decay The differential branching fraction with respect to the dimuon invariant mass squared, and the $C\!P$ asymmetry of the $B^\pm\to\pi^\pm\mu^+\mu^-$ decay are measured for the first time. [...] CERN-PH-EP-2015-219 ; LHCB-PAPER-2015-035. - 2015. Fulltext - Previous draft version - Related data file(s)

2015-09-04
14:59
 Measurement of ${C\!P}$ violation parameters and polarisation fractions in ${B_s^0\to J/\psi \overline{K}^{*0}}$ decays The first measurement of ${C\!P}$ asymmetries in the decay ${B_s^0\to J/\psi \overline{K}^{*}(892)^{0}}$ and an updated measurement of its branching fraction and polarisation fractions are presented. [...] CERN-PH-EP-2015-224 ; LHCB-PAPER-2015-034. - 2015. Fulltext - Previous draft version - Related data file(s)

2015-09-04
11:48
 Measurement of forward $J/\psi$ production cross-sections in $pp$ collisions at $\sqrt{s}=13$ TeV The production of $J/\psi$ mesons in proton-proton collisions at a centre-of-mass energy of $\sqrt{s}=13$ TeV is studied with the LHCb detector. [...] CERN-PH-EP-2015-222 ; LHCB-PAPER-2015-037. - 2015. Fulltext - Previous draft version - Related data file(s)

2015-09-04
09:07
 The optical links for the trigger upgrade of the Drift Tube in CMS / De Remigis, Paolo (INFN, Turin) /CMS Collaboration The first phase of the upgrade of the electronics of Drift Tubes (DT)in the CMS experiment is reported. It consists of the translation of the readoutand trigger data from electrical into optical and their transmission from the CMSexperimental cavern to the counting room. [...] CMS-CR-2015-145.- Geneva : CERN, 2015 - 4 p. Fulltext: PDF; In : 24th Incontri di Fisica delle Alte Energie, Rome, Italy, 8 - 10 Apr 2015

2015-09-04
09:07
 Development and performance of Triple-GEM detectors for the Upgrade of the Muon System of the CMS experiment / Vai, Ilaria (INFN, Pavia ; Pavia U.) The CMS Collaboration is evaluating GEM detectors for the upgrade of the muon system. This contribution will focus on the R and D performed on chambers design features and will discuss the performance of the upgraded detector.. CMS-CR-2015-143.- Geneva : CERN, 2015 - 4 p. Fulltext: PDF; In : 24th Incontri di Fisica delle Alte Energie, Rome, Italy, 8 - 10 Apr 2015

2015-09-04
09:07
 Impact of the GE1/1 upgrade on CMS muon system performance / Magnani, Alice (INFN, Pavia ; Pavia U.) During the future LHC upgrade planned in 2018, the forward endcap region of the CMS muon spectrometer will be upgraded with GEM chambers. GEM technology is able to withstand the radiation environment expected in the forward region. [...] CMS-CR-2015-142.- Geneva : CERN, 2015 - 6 p. Fulltext: PDF; In : 24th Incontri di Fisica delle Alte Energie, Rome, Italy, 8 - 10 Apr 2015

2015-09-04
09:07
 Pilot System for the Phase 1 Pixel Upgrade / Akgun, Bora (Rice U.) /CMS Collaboration The CMS phase 1 pixel upgrade is planned for installation in 2016-2017, incorporating new front-end ASICs with digital 400 Mbps data links to handle a higher instantaneous luminosity of up to 2.5 $x$ 10$^{34}$ cm$^{-2}$ s$^{-1}$ and trigger rates of 100 kHz with bunch spacing scenarios of 25 or 50 ns. The new digital readout requires new back-end electronics incorporating faster optical receivers and firmware for decoding the new data format. [...] CMS-CR-2015-139.- Geneva : CERN, 2015 - 8 p. Fulltext: PDF; In : 24th International Workshop on Vertex Detectors, Santa Fe, New Mexico, United States, 1 - 5 Jun 2015

2015-09-04
09:07
 Search for Heavy Neutrinos in di-lepton and di-jet events / Alunni Solestizi, Luisa (INFN, Perugia ; Perugia U.) /CMS Collaboration The di-lepton and di-jet final state is sensitive to many theoretical modelsbeyond the Standard Model, including scalar and vector leptoquarks of thethree generations and heavy Majorana neutrinos, arising from the seesawmechanism, also in the context of a LR-symmetry extension or in a compo-siteness scenario.The most recent CMS results have shown a signicant excess in the di-electron and di-jet channel, in two indipendent analysis one is a search forheavy neutrinos, deriving from the LR-symmetry extension and the otherlooks for a pair-production of first generation scalar leptoquarks, both per-formed at 8 TeV. No excess has been observed in the di-muon and di-jetchannel; while the di-tau and di-jet signature has not yet been explored forthe heavy neutrinos specific search, but only for the leptoquarks, with a b ort jet tagging.A benchmark process with a same flavour di-lepton plus di-jet signature, inthe frame of composite neutrinos and contact interactions, is taken into con-sideration to clarify the nature of the excess and to extend the mass limit forthe heavy neutrinos, exploiting the run 2 of CMS.. CMS-CR-2015-113.- Geneva : CERN, 2015 - 6 p. Fulltext: PDF; In : 24th Incontri di Fisica delle Alte Energie, Rome, Italy, 8 - 10 Apr 2015

2015-09-04
09:03
 Simulation studies on precise timing information during High Luminosity LHC. / Pernie, Luca (Brussels U.) /CMS Collaboration We present prospects for the usage of precise timing information during the high luminosity phase of the LHC (HL-LHC) at the CMS experiment. During the HL-LHC the instantaneous luminosity is estimated to be greater than 10$^{34}$ cm$^{-2}$s$^{-1}$, resulting in about 140 simultaneous proton-proton collisions (pileup) that occur every 25 nsec.\\ The time information can be exploited to improve the object reconstruction, for instance obtaining an alternative vertex determination, based on pure timing information, with a O(cm) resolution. This is particularly relevant in events with low track multiplicity (e.g. $H \rightarrow \gamma\gamma$), where the vertex cannot be precisely determined with tracking information. A time requirement can be also used to reduce the occupancy in the electromagnetic calorimeter (ECAL), removing the energy deposits with a time not compatible to the one expected from a particle coming from the hard collision. This may have important consequences in many aspects: reduction of event size, improvement of photon and jet energy resolution.. CMS-CR-2015-101.- Geneva : CERN, 2015 - 5 p. Fulltext: PDF; In : 24th Incontri di Fisica delle Alte Energie, Rome, Italy, 8 - 10 Apr 2015

2015-09-04
08:44
 CMS-TOTEM Precision Proton Spectrometers CT-PPS / Albrow, Michael Glen (Fermilab) /CMS Collaboration The CMS-TOTEM Precision Proton Spectrometer, CT-PPS, is an approved project to add 3D silicon tracking and quartz Cherenkov timing detectors in Roman pots at z = +/- 210 m from the CMS collision point to study final states p + X + p. The central state X can be a W-pair from photon-photon interactions, a set of high-ET jets from gluon collisions, among others, with M(X) obtained directly as well as from the two outgoing protons. [...] CMS-CR-2015-135.- Geneva : CERN, 2015 - 7 p. Fulltext: PDF; In : XXIII International Workshop on Deep-Inelastic Scattering and Related Subjects, Dallas, Tx, United States Of America, 27 Apr - 1 May 2015