V. Karimäki

Silicon beam telescope for CMS detector tests

Abstract A beam telescope providing precision track measurements as reference for other detectors has been upgraded in the CERN H2 test beam. The apparatus was completely rebuilt from the detector wafers and front-end electronics to the data acquisition system. The new detector setup consists of eight 5.6×5.6 cm 2 sized DC coupled silicon microstrip detectors. Typical position resolution values of about 7.5 μm were measured. Details of the setup are described and results from the recent beam tests are reported.

Performance and calibration studies of silicon strip detectors in a test beam

Abstract Performance of single-sided DC-coupled silicon strip detectors is studied in the CERN H2 test beam. A great emphasis is put on the calibration of the detector response as well as on the geometric alignment of the detector planes. Performance results are presented for different angles of incidence for the particles.

Measurement of angular parameters from the decay B-0 -> K*(0)mu(+)mu(-) in proton-proton collisions at root s=8 TeV

Angular distributions of the decay B0 → K∗0μ+μ− are studied using a sample of proton-proton collisions at √ s = 8 TeV collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 20.5 fb−1. An angular analysis is performed to determine the P1 and P′ 5 parameters, where the P ′ 5 parameter is of particular interest because of recent measurements that indicate a potential discrepancy with the standard model predictions. Based on a sample of 1397 signal events, the P1 and P′ 5 parameters are determined as a function of the dimuon invariant mass squared. The measurements are in agreement with predictions based on the standard model. Published in Physics Letters B as doi:10.1016/j.physletb.2018.04.030. c

Search for excited quarks of light and heavy flavor in gamma plus jet final states in proton-proton collisions at root s=13 TeV

A search is presented for excited quarks of light and heavy flavor that decay to γ+jet final states. The analysis is based on data corresponding to an integrated luminosity of 35.9 fb−1 collected by the CMS experiment in proton–proton collisions at s=13TeV at the LHC. A signal would appear as a resonant contribution to the invariant mass spectrum of the γ+jet system, above the background expected from standard model processes. No resonant excess is found, and upper limits are set on the product of the excited quark cross section and its branching fraction as a function of its mass. These are the most stringent limits to date in the γ+jet final state, and exclude excited light quarks with masses below 5.5u202fTeV and excited b quarks with masses below 1.8u202fTeV, assuming standard model like coupling strengths.

Search for anomalous couplings in boosted WW/WZ -> l nu q(q)over-bar production in proton-proton collisions at root s=8TeV

This Letter presents a search for new physics manifested as anomalous triple gauge boson couplings in WW and WZ diboson production in proton-proton collisions. The search is performed using events containing a W boson that decays leptonically and a W or Z boson whose decay products are merged into a single reconstructed jet. The data, collected at √ s = 8 TeV with the CMS detector at the LHC, correspond to an integrated luminosity of 19 fb−1. No evidence for anomalous triple gauge couplings is found and the following 95% confidence level limits are set on their values: λ ([−0.011, 0.011]), ∆κγ ([−0.044, 0.063]), and ∆gZ 1 ([−0.0087, 0.024]). These limits are also translated into their effective field theory equivalents: cWWW/Λ ([−2.7, 2.7]TeV−2), cB/Λ ([−14, 17]TeV−2), and cW/Λ ([−2.0, 5.7]TeV−2). Published in Physics Letters B as doi:10.1016/j.physletb.2017.06.009. c

Measurement of the t(t)over-bar production cross section in the all-jets final state in pp collisions at root s=8TeV

The cross section for

Measurement of the ratio of the production cross sections times branching fractions of B-c(+/-) -> J/psi pi(+/-) and B-+/- -> J/psi K-+/- and B(B-c(+/-) -> J/psi pi(+/-)pi(+/-)pi(-/+))/B(B-c(+/-) -> J/psi pi(+/-)) in pp collisions at root s=7 Tev

mathrm{t}overline{{mathrm{t}}}

Track-Based Alignment of Composite Detector Structures

tt¯ production in the all-jets final state is measured in pp collisions at a centre-of-mass energy of 8xa0