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Fulltext Searches for physics beyond the standard model with the M T 2 variable in hadronic final states with and without disappearing tracks in proton-proton collisions at s = 13 Te

Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Bergauer T, Brandstetter J, et al.

Eur Phys J C Part Fields, 2020;80(1):3.
PMID: 31976987 DOI: 10.1140/epjc/s10052-019-7493-x

Two related searches for phenomena beyond the standard model (BSM) are performed using events with hadronic jets and significant transverse momentum imbalance. The results are based on a sample of proton-proton collisions at a center-of-mass energy of 13 Te , collected by the CMS experiment at the LHC in 2016-2018 and corresponding to an integrated luminosity of 137 fb - 1 . The first search is inclusive, based on signal regions defined by the hadronic energy in the event, the jet multiplicity, the number of jets identified as originating from bottom quarks, and the value of the kinematic variable M T 2 for events with at least two jets. For events with exactly one jet, the transverse momentum of the jet is used instead. The second search looks in addition for disappearing tracks produced by BSM long-lived charged particles that decay within the volume of the tracking detector. No excess event yield is observed above the predicted standard model background. This is used to constrain a range of BSM models that predict the following: the pair production of gluinos and squarks in the context of supersymmetry models conserving R-parity, with or without intermediate long-lived charginos produced in the decay chain; the resonant production of a colored scalar state decaying to a massive Dirac fermion and a quark; or the pair production of scalar and vector leptoquarks each decaying to a neutrino and a top, bottom, or light-flavor quark. In most of the cases, the results obtained are the most stringent constraints to date.
Fulltext Tranexamic acid to improve functional status in adults with spontaneous intracerebral haemorrhage: the TICH-2 RCT

Sprigg N, Flaherty K, Appleton JP, Al-Shahi Salman R, Bereczki D, Beridze M, et al.

Health Technol Assess, 2019 07;23(35):1-48.
PMID: 31322116 DOI: 10.3310/hta23350

BACKGROUND: Tranexamic acid reduces death due to bleeding after trauma and postpartum haemorrhage.
OBJECTIVE: The aim of the study was to assess if tranexamic acid is safe, reduces haematoma expansion and improves outcomes in adults with spontaneous intracerebral haemorrhage (ICH).
DESIGN: The TICH-2 (Tranexamic acid for hyperacute primary IntraCerebral Haemorrhage) study was a pragmatic, Phase III, prospective, double-blind, randomised placebo-controlled trial.
SETTING: Acute stroke services at 124 hospitals in 12 countries (Denmark, Georgia, Hungary, Ireland, Italy, Malaysia, Poland, Spain, Sweden, Switzerland, Turkey and the UK).
PARTICIPANTS: Adult patients (aged ≥ 18 years) with ICH within 8 hours of onset.
EXCLUSION CRITERIA: Exclusion criteria were ICH secondary to anticoagulation, thrombolysis, trauma or a known underlying structural abnormality; patients for whom tranexamic acid was thought to be contraindicated; prestroke dependence (i.e. patients with a modified Rankin Scale [mRS] score > 4); life expectancy 4.5 hours after stroke onset. Pragmatic inclusion criteria led to a heterogeneous population of participants, some of whom had very large strokes. Although 12 countries enrolled participants, the majority (82.1%) were from the UK.
CONCLUSIONS: Tranexamic acid did not affect a patient's functional status at 90 days after ICH, despite there being significant modest reductions in early death (by 7 days), haematoma expansion and SAEs, which is consistent with an antifibrinolytic effect. Tranexamic acid was safe, with no increase in thromboembolic events.
FUTURE WORK: Future work should focus on enrolling and treating patients early after stroke and identify which participants are most likely to benefit from haemostatic therapy. Large randomised trials are needed.
TRIAL REGISTRATION: Current Controlled Trials ISRCTN93732214.
FUNDING: This project was funded by the National Institute for Health Research Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 23, No. 35. See the NIHR Journals Library website for further project information. The project was also funded by the Pragmatic Trials, UK, funding call and the Swiss Heart Foundation in Switzerland.
Fulltext Measurements of the [Formula: see text] production cross section in lepton+jets final states in pp collisions at 8 [Formula: see text] and ratio of 8 to 7 [Formula: see text] cross sections

Khachatryan V, Sirunyan AM, Tumasyan A, Adam W, Asilar E, Bergauer T, et al.

Eur Phys J C Part Fields, 2017;77(1):15.
PMID: 28260978 DOI: 10.1140/epjc/s10052-016-4504-z

A measurement of the top quark pair production ([Formula: see text]) cross section in proton-proton collisions at the centre-of-mass energy of 8[Formula: see text] is presented using data collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 19.6[Formula: see text]. This analysis is performed in the [Formula: see text] decay channels with one isolated, high transverse momentum electron or muon and at least four jets, at least one of which is required to be identified as originating from hadronization of a b quark. The calibration of the jet energy scale and the efficiency of b jet identification are determined from data. The measured [Formula: see text] cross section is [Formula: see text]. This measurement is compared with an analysis of 7[Formula: see text] data, corresponding to an integrated luminosity of 5.0[Formula: see text], to determine the ratio of 8[Formula: see text] to 7[Formula: see text] cross sections, which is found to be [Formula: see text]. The measurements are in agreement with QCD predictions up to next-to-next-to-leading order.
Search for top squark and Higgsino production using diphoton Higgs boson decays

Chatrchyan S, Khachatryan V, Sirunyan AM, Tumasyan A, Adam W, Bergauer T, et al.

Phys Rev Lett, 2014 Apr 25;112(16):161802.
PMID: 24815637

Results are presented of a search for a "natural" supersymmetry scenario with gauge mediated symmetry breaking. It is assumed that only the supersymmetric partners of the top quark (the top squark) and the Higgs boson (Higgsino) are accessible. Events are examined in which there are two photons forming a Higgs boson candidate, and at least two b-quark jets. In 19.7 fb-1 of proton-proton collision data at s=8 TeV, recorded in the CMS experiment, no evidence of a signal is found and lower limits at the 95% confidence level are set, excluding the top squark mass below 360 to 410 GeV, depending on the Higgsino mass.