47 research outputs found

    A search for new physics in central exclusive production using the missing mass technique with the CMS detector and the CMS-TOTEM precision proton spectrometer

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    A generic search is presented for the associated production of a Z boson or a photon with an additional unspecified massive particle X, pp → pp + Z/γ + X, in proton-tagged events from proton–proton collisions at √s = 13 TeV, recorded in 2017 with the CMS detector and the CMS-TOTEM precision proton spectrometer. The missing mass spectrum is analysed in the 600–1600 GeV range and a fit is performed to search for possible deviations from the background expectation. No significant excess in data with respect to the background predictions has been observed. odelindependent upper limits on the visible production cross section of pp → pp + Z/γ + X are set

    Measurement of single-diffractive dijet production in proton-proton collisions at root s=8 TeV with the CMS and TOTEM experiments

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    A Publisher's Erratum to this article was published on 03 May 2021. https://doi.org/10.1140/epjc/s10052-021-08863-wPeer reviewe

    Measurement of single-diffractive dijet production in proton–proton collisions at s=8TeV\sqrt{s} = 8\,\text {Te}\text {V} with the CMS and TOTEM experiments

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    Measurements are presented of the single-diffractive dijet cross section and the diffractive cross section as a function of the proton fractional momentum loss ξ ξ and the four-momentum transfer squared t. Both processes p p → p X p p → p X and p p → X p p p → X p , i.e. with the proton scattering to either side of the interaction point, are measured, where X X includes at least two jets; the results of the two processes are averaged. The analyses are based on data collected simultaneously with the CMS and TOTEM detectors at the LHC in proton–proton collisions at s √ =8TeV s=8TeV during a dedicated run with β ∗ =90m β∗=90m at low instantaneous luminosity and correspond to an integrated luminosity of 37.5nb −1 37.5nb−1 . The single-diffractive dijet cross section σ p X jj σjj p X , in the kinematic region ξ<0.1 ξ<0.1 , 0.03<|t|<1GeV 2 0.03<|t|<1GeV2 , with at least two jets with transverse momentum p T >40GeV pT>40GeV , and pseudorapidity |η|<4.4 |η|<4.4 , is 21.7±0.9(stat) +3.0 −3.3 (syst)±0.9(lumi)nb 21.7±0.9(stat)−3.3+3.0(syst)±0.9(lumi)nb . The ratio of the single-diffractive to inclusive dijet yields, normalised per unit of ξ ξ , is presented as a function of x, the longitudinal momentum fraction of the proton carried by the struck parton. The ratio in the kinematic region defined above, for x values in the range −2.9≤log 10 x≤−1.6 −2.9≤log10⁡x≤−1.6 , is R=(σ p X jj /Δξ)/σ jj =0.025±0.001(stat)±0.003(syst) R=(σjj p X /Δξ)/σjj=0.025±0.001(stat)±0.003(syst) , where σ p X jj σjj p X and σ jj σjj are the single-diffractive and inclusive dijet cross sections, respectively. The results are compared with predictions from models of diffractive and nondiffractive interactions. Monte Carlo predictions based on the HERA diffractive parton distribution functions agree well with the data when corrected for the effect of soft rescattering between the spectator partons

    Erratum to: Measurement of single-diffractive dijet production in proton–proton collisions at s=8TeV\sqrt{s} = 8\,\text {Te}\text {V} with the CMS and TOTEM experiments

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    Search for strongly interacting massive particles generating trackless jets in proton-proton collisions at s = 13 TeV

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    A search for dark matter in the form of strongly interacting massive particles (SIMPs) using the CMS detector at the LHC is presented. The SIMPs would be produced in pairs that manifest themselves as pairs of jets without tracks. The energy fraction of jets carried by charged particles is used as a key discriminator to suppress efficiently the large multijet background, and the remaining background is estimated directly from data. The search is performed using proton-proton collision data corresponding to an integrated luminosity of 16.1 fb - 1 , collected with the CMS detector in 2016. No significant excess of events is observed above the expected background. For the simplified dark matter model under consideration, SIMPs with masses up to 100 GeV are excluded and further sensitivity is explored towards higher masses

    Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study

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    Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28–2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65–3·22], p\textless0·0001), American Society of Anesthesiologists grades 3–5 versus grades 1–2 (2·35 [1·57–3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01–2·39], p=0·046), emergency versus elective surgery (1·67 [1·06–2·63], p=0·026), and major versus minor surgery (1·52 [1·01–2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research

    Search for strongly interacting massive particles generating trackless jets in proton–proton collisions at s√ = 13 TeV

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    Data Availability Statement: This manuscript has no associated data or the data will not be deposited. [Authors’ comment: Release and preservation of data used by the CMS Collaboration as the basis for publications is guided by the CMS policy as stated in “CMS data preservation, re-use and open access policy” (https://cms-docdb.cern.ch/cgi-bin/ PublicDocDB/RetrieveFile?docid=6032&filename=CMSDataPolicyV1. 2.pdf&version=2).]Copyright © 2022 The Authors. A search for dark matter in the form of strongly interacting massive particles (SIMPs) using the CMS detector at the LHC is presented. The SIMPs would be produced in pairs that manifest themselves as pairs of jets without tracks. The energy fraction of jets carried by charged particles is used as a key discriminator to suppress efficiently the large multijet background, and the remaining background is estimated directly from data. The search is performed using proton–proton collision data corresponding to an integrated luminosity of 16.1fb−1, collected with the CMS detector in 2016. No significant excess of events is observed above the expected background. For the simplified dark matter model under consideration, SIMPs with masses up to 100GeV are excluded and further sensitivity is explored towards higher masses.SCOAP3

    Rotura del ligamento cruzado posterior de la rodilla asociada a fractura de fémur o tibia homolateral

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    Los autores llaman la atención sobre la frecuente asociación de roturas del ligamento cruzado posterior (LCP) a ciertos tipos de fractura del miembro inferior Se revisan 10 casos: 6 asociados a fractura de fémur, y 4 casos asociados a fractura de tibia. Destacan en todos la igualdad en el mecanismo de producción y la frecuencia con que pasa desapercibida la lesión del ligamento hasta la completa resolución de la fractura acompañante, con un peor pronóstico del tratamiento mediante plastias sustitutivas y no mediante simple icinserción en la fase aguda. Por lo tanto, ante todo traumatizado con fracturas de fémur y/o de tibia producidas con la extremidad en flexión (accidente de moto, choque frontal) se debe sospechar la lesión del LCP, explorarlo clínica y radiográficamente y tratarlo cuando hayamos estabilizado la fractura acompañante

    Osteocondrítis disecante de la rodilla: Cambios artrósicos a largo plazo y factores pronósticos

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    El objetivo del estudio es analizar el efecto del pinzamiento articular en los resultados clínicos obtenidos a largo plazo tras diferentes métodos de tratamiento quirúrgico de la osteocondritis disecante de rodilla; asimismo se valora qué influencia tiene en su aparición factores como la edad del paciente, localización, estabilidad, extensión, tratamiento y tiempo de evolución de la lesión. Se realizó una revisión retrospectiva de 30 pacientes (22 hombres y ocho mujeres), cinco pacientes con afectación bilateral. La edad media fue de 26 años. E l tratamiento quirúrgico fue: reinserción del fragmento osteocondral en su lecho en 11 rodillas (siete con agujas de Smillie y cuatro con tornillos), exéresis del fragmento osteocondral en 24 (aislada en nueve, asociada a perforaciones del lecho en nueve e injerto osteocartilaginoso autólogo obtenido de la cara externa de la tróclea femoral en seis). Se realizó una valoración clínica y radiográfica postoperatoria. E l tiempo de evolución medio fue de 14 años. Los resultados clínicos obtenidos con las diferentes técnicas de tratamiento fueron similares, a excepción de los obtenidos con el injerto osteocartilaginoso autólogo, que fueron peores. Referían ausencia o dolor leve un 66 a 77% de los pacientes y sólo un 50% de los tratados con injerto osteocartilaginoso autólogo. El dolor y el balance articular se relacionaron con el pinzamiento articular; así, cuanto menor es la distancia entre las superficies articulares mayor es el dolor y peor el balance articular (p < 0,05). Aquellos pacientes que tenían mayor edad en el momento del tratamiento presentaron un mayor pinzamiento articular (p < 0,05). Aquellos pacientes que tenían mayor edad en el momento del tratamiento presentaron un mayor pinzamiento articular (p < 0,05), localización de la lesión en zonas de carga (inferocentral medial y lateral), tiempo de evolución superior a 16 años y los tratados mediante injerto osteocartilaginoso autólogo. No existieron diferencias estadísticamente significativas en el pinzamiento articular según la extensión y estabilidad del fragmento osteocondral
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