1,477 research outputs found

    CMS-HF Calorimeter Upgrade for Run II

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    CMS-HF Calorimeters have been undergoing a major upgrade for the last couple of years to alleviate the problems encountered during Run I, especially in the PMT and the readout systems. In this poster, the problems caused by the old PMTs installed in the detectors and their solutions will be explained. Initially, regular PMTs with thicker windows, causing large Cherenkov radiation, were used. Instead of the light coming through the fibers from the detector, stray muons passing through the PMT itself produce Cherenkov radiation in the PMT window, resulting in erroneously large signals. Usually, large signals are the result of very high-energy particles in the calorimeter and are tagged as important. As a result, these so-called window events generate false triggers. Four-anode PMTs with thinner windows were selected to reduce these window events. Additional channels also help eliminate such remaining events through algorithms comparing the output of different PMT channels. During the EYETS 16/17 period in the LHC operations, the final components of the modifications to the readout system, namely the two-channel front-end electronics cards, are installed. Complete upgrade of the HF Calorimeter, including the preparations for the Run II will be discussed in this poster, with possible effects on the eventual data taking.Comment: Presented at The Fifth Annual Conference on Large Hadron Collider Physics Shanghai Jiao Tong University, Shanghai, China May 15-20, 201

    Radiation-Hardness Measurements of High OH−OH^{-} Content Quartz Fibres Irradiated with 24 GeV Protons up to 1.25 Grad

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    We investigated the darkening of two high OH- content quartz fibres irradiated with 24 GeV protons at the Cern PS facility IRRAD. The two tested fibres have a 0.6 mm quartz core diameter, one with hard plastic cladding (qp) and the other with quartz cladding (qq). These fibres were exposed at about 1.25 Gigarad in 3 weeks. The fibres became opaque below 380nm, and in the range 580-650 nm. The darkening under irradiation and damage recovery after irradiation as a function of dose and time are similar to what we observed with electrons. The typical attenuation at 455 nm are 1.44 + - 0.22 and 2.20 + - 0.15 dB/m at 100 Mrad for qp and qq fibres, respectively. The maximum damage recovery is also observed near this wavelength

    Comparison of Mean Platelet Volume Values between Patients with Nasal Polyp and Healthy Individuals

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    Objective:Nasal Polyp (NP) and Allergic Rhinitis (AR) are frequently seen in common. It has been reported that there is an increase in the risk of atherosclerosis in allergic patients. In our study, we aimed to evaluate Mean Platelet Volume (MPV) values in patients with NP, which is used as a marker of atherosclerosis.Methods:Seventy-five patients who underwent functional endoscopic sinus surgery (FESS) with a diagnosis of NP were reviewed. Seventy-five age-matched healthy individuals without AR made up the control group. Values of white blood cell (WBC), platelet (PLT), hemoglobilin (Hb) and MPV were evaluated.Results:MPV values were found to be low in patients with NP 7.89±1.02 fL compared to control group 8.32±1.42 fL. This finding was statistically significant.Conclusion:It was found that MPV values are significantly low in patients with NP than control group

    Plasmonic titanium nitride nanohole arrays for refractometric sensing

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    Group IVB metal nitrides have attracted great interest as alternative plasmonic materials. Among them, titanium nitride (TiN) stands out due to the ease of deposition and relative abundance of Ti compared to those of Zr and Hf metals. Even though they do not have Au or Ag-like plasmonic characteristics, they offer many advantages, from high mechanical stability to refractory behavior and complementary metal oxide semiconductor-compatible fabrication to tunable electrical/optical properties. In this study, we utilized reactive RF magnetron sputtering to deposit plasmonic TiN thin films. The flow rate and ratio of Ar/N2 and oxygen scavenging methods were optimized to improve the plasmonic performance of TiN thin films. The stoichiometry and structure of the TiN thin films were thoroughly investigated to assess the viability of the optimized operation procedures. To assess the plasmonic performance of TiN thin films, periodic nanohole arrays were perforated on TiN thin films by using electron beam lithography and reactive ion etching methods. The resulting TiN periodic nanohole array with varying periods was investigated by using a custom microspectroscopy setup for both reflection and transmission characteristics in various media to underline the efficacy of TiN for refractometric sensing.101111321 ; EP/Y030273/

    Impact of Reducing Irritative Symptoms in Non-Muscle Invasive Bladder Cancer During BCG Instillation: A Pilot Study

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    INTRODUCTION: We evaluated use of anticholinergics, mirabegron, and combination of anticholinergics with mirabegron during Bacillus Calmette-GuĂ©rin (BCG) instillation for reducing irritative symptoms in patients with non-muscle invasive bladder cancer (NMIBC). METHODS: Prospectively recorded data of NMIBC patients receiving BCG were retrospectively evaluated between August 2015 and April 2019. Patients with low-grade T1 solitary papillary lesions <4 cm were included in the study. Validated questionnaires (OAB-V8) for irritative symptoms adapted to Turkish language, and QoL index forms were filled out by the study participants. OAB-V8 scores of ≥8 were considered as an indication to start medical treatment for irritative symptoms. Groups were formed according to daily used anticholinergic drugs and combinations as follows: Group 1, tolterodine; Group 2, solifenacin 5mg; Group 3, mirabegron, and Group 4, mirabegron with solifenacin 5 mg. RESULTS: Mean follow- up period was 20.4+-6.8 months. There were 132 patients [110 men (83%) and 22 (17%) women] with irritative symptoms and NMIBC. Mean age of the study population was 59.7+-12.4 years. The OAB-V8 scores and QoL indexes significantly improved with all drugs. However, in subgroup analyses, Group 4 provided the most dramatic improvement in OAB-V8 and QoL index scores (P=0.02 for both). The longest in time to micturition was recorded in Group 4 (P=0.04). Tumour recurrence was similar for groups 12 months after BCG instillation (P=0.9), however the least recurrence was observed in Group 4. DISCUSSION AND CONCLUSION: Combination of solifecacin and mirabegron can reduce irritative symptoms, improve QoL, and prolong time to micturition, during BCG instillation in selected NMIBC patients. This combination may also decrease recurrence rates in this patient population

    Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV

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    A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7 TeV is presented. The data were collected at the LHC, with the CMS detector, and correspond to an integrated luminosity of 4.6 inverse femtobarns. No significant excess is observed above the background expectation, and upper limits are set on the Higgs boson production cross section. The presence of the standard model Higgs boson with a mass in the 270-440 GeV range is excluded at 95% confidence level.Comment: Submitted to JHE

    Combined search for the quarks of a sequential fourth generation

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    Results are presented from a search for a fourth generation of quarks produced singly or in pairs in a data set corresponding to an integrated luminosity of 5 inverse femtobarns recorded by the CMS experiment at the LHC in 2011. A novel strategy has been developed for a combined search for quarks of the up and down type in decay channels with at least one isolated muon or electron. Limits on the mass of the fourth-generation quarks and the relevant Cabibbo-Kobayashi-Maskawa matrix elements are derived in the context of a simple extension of the standard model with a sequential fourth generation of fermions. The existence of mass-degenerate fourth-generation quarks with masses below 685 GeV is excluded at 95% confidence level for minimal off-diagonal mixing between the third- and the fourth-generation quarks. With a mass difference of 25 GeV between the quark masses, the obtained limit on the masses of the fourth-generation quarks shifts by about +/- 20 GeV. These results significantly reduce the allowed parameter space for a fourth generation of fermions.Comment: Replaced with published version. Added journal reference and DO

    Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV

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    Results are presented from a search for a W' boson using a dataset corresponding to 5.0 inverse femtobarns of integrated luminosity collected during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV. The W' boson is modeled as a heavy W boson, but different scenarios for the couplings to fermions are considered, involving both left-handed and right-handed chiral projections of the fermions, as well as an arbitrary mixture of the two. The search is performed in the decay channel W' to t b, leading to a final state signature with a single lepton (e, mu), missing transverse energy, and jets, at least one of which is tagged as a b-jet. A W' boson that couples to fermions with the same coupling constant as the W, but to the right-handed rather than left-handed chiral projections, is excluded for masses below 1.85 TeV at the 95% confidence level. For the first time using LHC data, constraints on the W' gauge coupling for a set of left- and right-handed coupling combinations have been placed. These results represent a significant improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe

    Measurement of the t t-bar production cross section in the dilepton channel in pp collisions at sqrt(s) = 7 TeV

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    The t t-bar production cross section (sigma[t t-bar]) is measured in proton-proton collisions at sqrt(s) = 7 TeV in data collected by the CMS experiment, corresponding to an integrated luminosity of 2.3 inverse femtobarns. The measurement is performed in events with two leptons (electrons or muons) in the final state, at least two jets identified as jets originating from b quarks, and the presence of an imbalance in transverse momentum. The measured value of sigma[t t-bar] for a top-quark mass of 172.5 GeV is 161.9 +/- 2.5 (stat.) +5.1/-5.0 (syst.) +/- 3.6(lumi.) pb, consistent with the prediction of the standard model.Comment: Replaced with published version. Included journal reference and DO

    Search for New Physics with Jets and Missing Transverse Momentum in pp collisions at sqrt(s) = 7 TeV

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    A search for new physics is presented based on an event signature of at least three jets accompanied by large missing transverse momentum, using a data sample corresponding to an integrated luminosity of 36 inverse picobarns collected in proton--proton collisions at sqrt(s)=7 TeV with the CMS detector at the LHC. No excess of events is observed above the expected standard model backgrounds, which are all estimated from the data. Exclusion limits are presented for the constrained minimal supersymmetric extension of the standard model. Cross section limits are also presented using simplified models with new particles decaying to an undetected particle and one or two jets
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