836 research outputs found

    Top properties (excluding mass) and ancillary measurements

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    A review on recent top quark properties measurements by the ATLAS and CMS Collaborations in pp collisions at the LHC is presented.Comment: Talk at the 16th International Workshop on Top Quark Physics (Top2023), 24-29 September 202

    Evaluation of the Effect of 1,3-Bis(4-Phenyl)-1H-1,2,3- Triazolyl-2-Propanolol on Gene Expression Levels of JAK2–STAT3, NF-jB, and SOCS3 in Cells Cultured from Biopsies of Mammary Lesions

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    El presente artículo es el resultado de la evaluación del efecto de un bistriazol mediante la expresión génica de JAK2, STAT3, SOCS3 y NF-κB, vías involucradas en lesiones benignas de mama posiblemente dependiente del índice de masa corporal, dando así una relación entre el cáncer y obesidad. En este estudio se calculó la concentración inhibitoria 50 del bistriazol en cultivos celulares de pacientes con lesión benigna (Probit = 4.6 μM con IC= 95 %). En 63 mujeres que acudieron a realizarse biopsia en el Hospital Materno Perinatal "Mónica Pretellini Sáenz", 21 fueron con cáncer, se les tomaron medidas antropométricas y biopsia de la lesión en mama, en la cual se determinó expresión génica y se realizó cultivo celular con el bistriazol a la concentración de 4.6 μM. Se encontró que el cáncer de mama está relacionado con edad mayor de 50 años (P≤ 0.01), sobrepeso (P≤ 0.023) y circunferencia cintura mayor de 80 cm (P≤ 0.01). La expresión génica de JAK2, STAT3 y NF-κB fue mayor en el grupo de pacientes con cáncer en cuanto que SOCS3 resultó ser menor. La expresión después de haber sido sometida al bistriazol, disminuyó la expresión de JAK2 y STAT3, aumentó la expresión de SOCS3 y de NF-κB. Se concluye que esta molécula en desarrollo tiene efecto en la expresión génica de JAK2 y STAT3. Sin embargo, la vía de expresión NF-κB no esta marcadamente involucrada en la regulación de la inflamación.Breast cancer is the most frequent neoplasia in women and is responsible for approximately 13.8% of deaths per year for this gender. It has been suggested that JAK2, STAT3, and NF-κB gene expression is involved in this type of cancer. The objective of the present study was to determine the effect of bistriazole in these signaling pathways in patients with breast cancer and benign mammary lesions. The inhibitory concentration 50 of bistriazole was calculated in cell cultures of patients with benign lesions, Probit = 4.6 μM with IC = 95%. The study was performed by examining 63 women who submitted to mammary biopsies. Biopsies of the mammary lesions were performed, gene expression was determined, and cells were cultured in the presence of 4.6 μM bistriazole. We found that breast cancer is related to age greater than 50 (P ≤ 0.01), being overweight (P ≤ 0.023) and having a waist circumference larger than 80 cm (P ≤ 0.01). The gene expression of JAK2, STAT3, and NF-κB was higher in groups of patients with breast cancer, while SOCS3 expression was lower. After being exposed to bistriazole, the expression of JAK2 and STAT3 decreased, and the expression of SOCS3 and NF-κB increased. In conclusion, this molecule in development has an effect on the gene expression of JAK3 and STAT3; nevertheless, the lack of change in NF-κB indicates that it is not a regulator of inflammation, and therefore, more studies should be performed

    The CMS Phase-1 pixel detector upgrade

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    The CMS detector at the CERN LHC features a silicon pixel detector as its innermost subdetector. The original CMS pixel detector has been replaced with an upgraded pixel system (CMS Phase-1 pixel detector) in the extended year-end technical stop of the LHC in 2016/2017. The upgraded CMS pixel detector is designed to cope with the higher instantaneous luminosities that have been achieved by the LHC after the upgrades to the accelerator during the first long shutdown in 2013–2014. Compared to the original pixel detector, the upgraded detector has a better tracking performance and lower mass with four barrel layers and three endcap disks on each side to provide hit coverage up to an absolute value of pseudorapidity of 2.5. This paper describes the design and construction of the CMS Phase-1 pixel detector as well as its performance from commissioning to early operation in collision data-taking.Peer reviewe

    Selection of the silicon sensor thickness for the Phase-2 upgrade of the CMS Outer Tracker

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    During the operation of the CMS experiment at the High-Luminosity LHC the silicon sensors of the Phase-2 Outer Tracker will be exposed to radiation levels that could potentially deteriorate their performance. Previous studies had determined that planar float zone silicon with n-doped strips on a p-doped substrate was preferred over p-doped strips on an n-doped substrate. The last step in evaluating the optimal design for the mass production of about 200 m2^{2} of silicon sensors was to compare sensors of baseline thickness (about 300 μm) to thinned sensors (about 240 μm), which promised several benefits at high radiation levels because of the higher electric fields at the same bias voltage. This study provides a direct comparison of these two thicknesses in terms of sensor characteristics as well as charge collection and hit efficiency for fluences up to 1.5 × 1015^{15} neq_{eq}/cm2^{2}. The measurement results demonstrate that sensors with about 300 μm thickness will ensure excellent tracking performance even at the highest considered fluence levels expected for the Phase-2 Outer Tracker

    Comparative evaluation of analogue front-end designs for the CMS Inner Tracker at the High Luminosity LHC

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    The CMS Inner Tracker, made of silicon pixel modules, will be entirely replaced prior to the start of the High Luminosity LHC period. One of the crucial components of the new Inner Tracker system is the readout chip, being developed by the RD53 Collaboration, and in particular its analogue front-end, which receives the signal from the sensor and digitizes it. Three different analogue front-ends (Synchronous, Linear, and Differential) were designed and implemented in the RD53A demonstrator chip. A dedicated evaluation program was carried out to select the most suitable design to build a radiation tolerant pixel detector able to sustain high particle rates with high efficiency and a small fraction of spurious pixel hits. The test results showed that all three analogue front-ends presented strong points, but also limitations. The Differential front-end demonstrated very low noise, but the threshold tuning became problematic after irradiation. Moreover, a saturation in the preamplifier feedback loop affected the return of the signal to baseline and thus increased the dead time. The Synchronous front-end showed very good timing performance, but also higher noise. For the Linear front-end all of the parameters were within specification, although this design had the largest time walk. This limitation was addressed and mitigated in an improved design. The analysis of the advantages and disadvantages of the three front-ends in the context of the CMS Inner Tracker operation requirements led to the selection of the improved design Linear front-end for integration in the final CMS readout chip

    Observation of the Production of Three Massive Gauge Bosons at root s=13 TeV

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    The first observation is reported of the combined production of three massive gauge bosons (VVV with V = W, Z) in proton-proton collisions at a center-of-mass energy of 13 TeV. The analysis is based on a data sample recorded by the CMS experiment at the CERN LHC corresponding to an integrated luminosity of 137 fb(-1). The searches for individualWWW, WWZ, WZZ, and ZZZ production are performed in final states with three, four, five, and six leptons (electrons or muons), or with two same-sign leptons plus one or two jets. The observed (expected) significance of the combinedVVV production signal is 5.7 (5.9) standard deviations and the corresponding measured cross section relative to the standard model prediction is 1.02(-0.23)(+0.26). The significances of the individual WWW and WWZ production are 3.3 and 3.4 standard deviations, respectively. Measured production cross sections for the individual triboson processes are also reported

    Measurement of prompt open-charm production cross sections in proton-proton collisions at root s=13 TeV

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    The production cross sections for prompt open-charm mesons in proton-proton collisions at a center-of-mass energy of 13TeV are reported. The measurement is performed using a data sample collected by the CMS experiment corresponding to an integrated luminosity of 29 nb(-1). The differential production cross sections of the D*(+/-), D-+/-, and D-0 ((D) over bar (0)) mesons are presented in ranges of transverse momentum and pseudorapidity 4 < p(T) < 100 GeV and vertical bar eta vertical bar < 2.1, respectively. The results are compared to several theoretical calculations and to previous measurements.Peer reviewe

    Search for a light pseudoscalar Higgs boson in the boosted mu mu tau tau final state in proton-proton collisions at root s=13 TeV

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    A search for a light pseudoscalar Higgs boson (a) decaying from the 125 GeV (or a heavier) scalar Higgs boson (H) is performed using the 2016 LHC proton-proton collision data at root s = 13 TeV, corresponding to an integrated luminosity of 35.9 fb(-1), collected by the CMS experiment. The analysis considers gluon fusion and vector boson fusion production of the H, followed by the decay H -> aa -> mu mu tau tau, and considers pseudoscalar masses in the range 3.6 aa -> mu mu tau tau, down to 1.5 (2.0)x10(-4) for m(H) = 125 (300) GeV. Model-dependent limits on B(H -> aa) are set within the context of two Higgs doublets plus singlet models, with the most stringent results obtained for Type-III models. These results extend current LHC searches for heavier a bosons that decay to resolved lepton pairs and provide the first such bounds for an H boson with a mass above 125 GeV.Peer reviewe

    Reconstruction of signal amplitudes in the CMS electromagnetic calorimeter in the presence of overlapping proton-proton interactions

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    A template fitting technique for reconstructing the amplitude of signals produced by the lead tungstate crystals of the CMS electromagnetic calorimeter is described. This novel approach is designed to suppress the contribution to the signal of the increased number of out-of-time interactions per beam crossing following the reduction of the accelerator bunch spacing from 50 to 25 ns at the start of Run 2 of the LHC. Execution of the algorithm is sufficiently fast for it to be employed in the CMS high-level trigger. It is also used in the offline event reconstruction. Results obtained from simulations and from Run 2 collision data (2015-2018) demonstrate a substantial improvement in the energy resolution of the calorimeter over a range of energies extending from a few GeV to several tens of GeV.Peer reviewe

    Development and validation of HERWIG 7 tunes from CMS underlying-event measurements

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    This paper presents new sets of parameters (“tunes”) for the underlying-event model of the HERWIG7 event generator. These parameters control the description of multiple-parton interactions (MPI) and colour reconnection in HERWIG7, and are obtained from a fit to minimum-bias data collected by the CMS experiment at s=0.9, 7, and 13Te. The tunes are based on the NNPDF 3.1 next-to-next-to-leading-order parton distribution function (PDF) set for the parton shower, and either a leading-order or next-to-next-to-leading-order PDF set for the simulation of MPI and the beam remnants. Predictions utilizing the tunes are produced for event shape observables in electron-positron collisions, and for minimum-bias, inclusive jet, top quark pair, and Z and W boson events in proton-proton collisions, and are compared with data. Each of the new tunes describes the data at a reasonable level, and the tunes using a leading-order PDF for the simulation of MPI provide the best description of the dat
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