Displaying publications 81 - 100 of 162 in total

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  1. Azimuthal Correlations within Exclusive Dijets with Large Momentum Transfer in Photon-Lead Collisions
    Tumasyan A, Adam W, Bergauer T, Dragicevic M, Del Valle AE, Frühwirth R, et al.
    Phys Rev Lett, 2023 Aug 04;131(5):051901.
    PMID: 37595238 DOI: 10.1103/PhysRevLett.131.051901
    The structure of nucleons is multidimensional and depends on the transverse momenta, spatial geometry, and polarization of the constituent partons. Such a structure can be studied using high-energy photons produced in ultraperipheral heavy-ion collisions. The first measurement of the azimuthal angular correlations of exclusively produced events with two jets in photon-lead interactions at large momentum transfer is presented, a process that is considered to be sensitive to the underlying nuclear gluon polarization. This study uses a data sample of ultraperipheral lead-lead collisions at sqrt[s_{NN}]=5.02  TeV, corresponding to an integrated luminosity of 0.38  nb^{-1}, collected with the CMS experiment at the LHC. The measured second harmonic of the correlation between the sum and difference of the two jet transverse momentum vectors is found to be positive, and rising, as the dijet transverse momentum increases. A well-tuned model that has been successful at describing a wide range of proton scattering data from the HERA experiments fails to describe the observed correlations, suggesting the presence of gluon polarization effects.
  2. Search for Nonresonant Pair Production of Highly Energetic Higgs Bosons Decaying to Bottom Quarks
    Tumasyan A, Adam W, Andrejkovic JW, Bergauer T, Chatterjee S, Damanakis K, et al.
    Phys Rev Lett, 2023 Jul 28;131(4):041803.
    PMID: 37566864 DOI: 10.1103/PhysRevLett.131.041803
    A search for nonresonant Higgs boson (H) pair production via gluon and vector boson (V) fusion is performed in the four-bottom-quark final state, using proton-proton collision data at 13 TeV corresponding to 138  fb^{-1} collected by the CMS experiment at the LHC. The analysis targets Lorentz-boosted H pairs identified using a graph neural network. It constrains the strengths relative to the standard model of the H self-coupling and the quartic VVHH couplings, κ_{2V}, excluding κ_{2V}=0 for the first time, with a significance of 6.3 standard deviations when other H couplings are fixed to their standard model values.
  3. Search for Exotic Higgs Boson Decays H→AA→4γ with Events Containing Two Merged Diphotons in Proton-Proton Collisions at sqrt[s]=13  TeV
    Tumasyan A, Adam W, Andrejkovic JW, Bergauer T, Chatterjee S, Damanakis K, et al.
    Phys Rev Lett, 2023 Sep 08;131(10):101801.
    PMID: 37739361 DOI: 10.1103/PhysRevLett.131.101801
    We present the first direct search for exotic Higgs boson decays H→AA, A→γγ in events with two photonlike objects. The hypothetical particle A is a low-mass spin-0 particle decaying promptly to a merged diphoton reconstructed as a single photonlike object. We analyze the data collected by the CMS experiment at sqrt[s]=13  TeV corresponding to an integrated luminosity of 136  fb^{-1}. No excess above the estimated background is found. We set upper limits on the branching fraction B(H→AA→4γ) of (0.9-3.3)×10^{-3} at 95% confidence level for masses of A in the range 0.1-1.2 GeV.
  4. Observation of Same-Sign WW Production from Double Parton Scattering in Proton-Proton Collisions at sqrt[s]=13  TeV
    Tumasyan A, Adam W, Andrejkovic JW, Bergauer T, Chatterjee S, Damanakis K, et al.
    Phys Rev Lett, 2023 Sep 01;131(9):091803.
    PMID: 37721845 DOI: 10.1103/PhysRevLett.131.091803
    The first observation of the production of W^{±}W^{±} bosons from double parton scattering processes using same-sign electron-muon and dimuon events in proton-proton collisions is reported. The data sample corresponds to an integrated luminosity of 138  fb^{-1} recorded at a center-of-mass energy of 13 TeV using the CMS detector at the CERN LHC. Multivariate discriminants are used to distinguish the signal process from the main backgrounds. A binned maximum likelihood fit is performed to extract the signal cross section. The measured cross section for production of same-sign W bosons decaying leptonically is 80.7±11.2(stat) _{-8.6}^{+9.5}(syst)±12.1(model)  fb, whereas the measured fiducial cross section is 6.28±0.81(stat)±0.69(syst)±0.37(model)  fb. The observed significance of the signal is 6.2 standard deviations above the background-only hypothesis.
  5. Fulltext Differential expression of senescence tumour markers and its implications on survival outcomes of breast cancer patients
    Pare R, Soon PS, Shah A, Lee CS
    PLoS One, 2019;14(4):e0214604.
    PMID: 30998679 DOI: 10.1371/journal.pone.0214604
    Breast cancer is a heterogeneous disease displaying different histopathological characteristics, molecular profiling and clinical behavior. This study describes the expression patterns of senescence markers P53, DEC1 and DCR2 and assesses their significance on patient survival as a single or combined marker with P16 or P14 using breast cancer progression series. One thousand and eighty (1080) patients with primary invasive ductal carcinoma, no special type, were recruited through an 11-year retrospective study period. We constructed tissue microarrays of normal, benign hyperplasia, ductal carcinoma in situ and invasive ductal carcinoma from each patient and performed immunohistochemical staining to study the protein expression. Statistical analysis includes Pearson chi-square, Kaplan-Meier log ran test and Cox proportional hazard regression were undertaken to determine the associations and predict the survival outcomes. P53, DEC1 and DCR2 expression correlated significantly with normal, benign, premalignant and malignant tissues with (p<0.05). The expression profile of these genes increases from normal to benign to premalignant and plateaued from premalignant to malignant phenotype. There is a significant association between P53 protein expression and age, grade, staging, lymphovascular invasion, estrogen receptor, progesterone receptor and HER2 whereas DCR2 protein expression significantly correlated with tumour grade, hormone receptors status and HER2 (p<0.05 respectively). P53 overexpression correlated with increased risk of relapse (p = 0.002) specifically in patients who did not receive hormone therapy (p = 0.005) or chemotherapy (p<0.0001). The combination of P53+/P16+ is significantly correlated with poor overall and disease-free survival, whereas a combination of P53+/P14+ is associated with worse outcome in disease-free survival (p<0.05 respectively). P53 overexpression appears to be a univariate predictor of poor disease-free survival. The expression profiles of DEC1 and DCR2 do not appear to correlate with patient survival outcomes. The combination of P53 with P16, rather P53 expression alone, appears to provide more useful clinical information on patient survival outcomes in breast cancer.
  6. Fulltext Elevated interleukin-25 and its association to Th2 cytokines in systemic lupus erythematosus with lupus nephritis
    Selvaraja M, Abdullah M, Arip M, Chin VK, Shah A, Amin Nordin S
    PLoS One, 2019;14(11):e0224707.
    PMID: 31697750 DOI: 10.1371/journal.pone.0224707
    Systemic lupus erythematosus (SLE) is an autoimmune disorder that is associated with lupus nephritis, initiated by the deposition of immune complexes in the kidney; subsequently, this induces the overexpression of cytokines. Lupus nephritis is known as one of the major clinical manifestations that affect the disease severity in SLE patients. An increased number of resident periglomerular and immune cells in the kidney has the potential to affect the equilibrium of different immune cell subsets, such as Th1, Th2, Th17, and Tregs, which may be central to the induction of tissue damage in kidney by exerting either proinflammatory or anti-inflammatory effects, or both. This equilibrium has yet to be confirmed, as new players such as IL-25 remain undiscovered. IL-25 is a cytokine of the IL-17 family, which stimulates Th2-mediated immune response when overly expressed. Thus, the aim of this research is to determine the plasma levels of IL-25 and Th2-associated cytokines (IL-4, IL-5, IL-6, IL-9, IL-10, IL-13) in SLE patients with (SLE-LN) and without lupus nephritis. Sixty-four (n = 64) SLE patients and fifteen (n = 15) healthy individuals were recruited. This study demonstrated that the IL-9, IL-10 and IL-25 had significantly increased expressions in SLE-LN, followed by SLE without LN, compared to healthy controls. Meanwhile, IL-5 and IL-6 had significantly reduced. No significant difference was observed with IL-13, while the level of IL-4 was undetectable. Furthermore, IL-9 and IL-10 were significantly correlated with the IL-25, and IL-25, IL-9 and IL-10 were positively correlated with the disease severity score, SLEDAI. In conclusion, IL-25 and its associated Th2 cytokines (IL-9 and IL-10) may be involved in SLE pathogenesis. These cytokines could be potential biomarkers in monitoring and predicting the disease severity during SLE pathogenesis.
  7. Fulltext Evaluating critical success factors in implementing E-learning system using multi-criteria decision-making
    Naveed QN, Qureshi MRN, Tairan N, Mohammad A, Shaikh A, Alsayed AO, et al.
    PLoS One, 2020;15(5):e0231465.
    PMID: 32365123 DOI: 10.1371/journal.pone.0231465
    Learning using the Internet or training through E-Learning is growing rapidly and is increasingly favored over the traditional methods of learning and teaching. This radical shift is directly linked to the revolution in digital computer technology. The revolution propelled by innovation in computer technology has widened the scope of E-Learning and teaching, whereby the process of exchanging information has been made simple, transparent, and effective. The E-Learning system depends on different success factors from diverse points of view such as system, support from the institution, instructor, and student. Thus, the effect of critical success factors (CSFs) on the E-Learning system must be critically analyzed to make it more effective and successful. This current paper employed the analytic hierarchy process (AHP) with group decision-making (GDM) and Fuzzy AHP (FAHP) to study the diversified factors from different dimensions of the web-based E-Learning system. The present paper quantified the CSFs along with its dimensions. Five different dimensions and 25 factors associated with the web-based E-Learning system were revealed through the literature review and were analyzed further. Furthermore, the influence of each factor was derived successfully. Knowing the impact of each E-Learning factor will help stakeholders to construct education policies, manage the E-Learning system, perform asset management, and keep pace with global changes in knowledge acquisition and management.
  8. UMobileNetV2 model for semantic segmentation of gastrointestinal tract in MRI scans
    Sharma N, Gupta S, Gupta D, Gupta P, Juneja S, Shah A, et al.
    PLoS One, 2024;19(5):e0302880.
    PMID: 38718092 DOI: 10.1371/journal.pone.0302880
    Gastrointestinal (GI) cancer is leading general tumour in the Gastrointestinal tract, which is fourth significant reason of tumour death in men and women. The common cure for GI cancer is radiation treatment, which contains directing a high-energy X-ray beam onto the tumor while avoiding healthy organs. To provide high dosages of X-rays, a system needs for accurately segmenting the GI tract organs. The study presents a UMobileNetV2 model for semantic segmentation of small and large intestine and stomach in MRI images of the GI tract. The model uses MobileNetV2 as an encoder in the contraction path and UNet layers as a decoder in the expansion path. The UW-Madison database, which contains MRI scans from 85 patients and 38,496 images, is used for evaluation. This automated technology has the capability to enhance the pace of cancer therapy by aiding the radio oncologist in the process of segmenting the organs of the GI tract. The UMobileNetV2 model is compared to three transfer learning models: Xception, ResNet 101, and NASNet mobile, which are used as encoders in UNet architecture. The model is analyzed using three distinct optimizers, i.e., Adam, RMS, and SGD. The UMobileNetV2 model with the combination of Adam optimizer outperforms all other transfer learning models. It obtains a dice coefficient of 0.8984, an IoU of 0.8697, and a validation loss of 0.1310, proving its ability to reliably segment the stomach and intestines in MRI images of gastrointestinal cancer patients.
  9. Fulltext Dopant engineering for ZnO electron transport layer towards efficient perovskite solar cells
    Zainal Abidin NA, Arith F, Noorasid NS, Sarkawi H, Mustafa AN, Safie NE, et al.
    RSC Adv, 2023 Nov 16;13(48):33797-33819.
    PMID: 38020037 DOI: 10.1039/d3ra04823c
    The conventional electron transport layer (ETL) TiO2 has been widely used in perovskite solar cells (PSCs), which have produced exceptional power conversion efficiencies (PCE), allowing the technology to be highly regarded and propitious. Nevertheless, the recent high demand for energy harvesters in wearable electronics, aerospace, and building integration has led to the need for flexible solar cells. However, the conventional TiO2 ETL layer is less preferred, where a crystallization process at a temperature as high as 450 °C is required, which degrades the plastic substrate. Zinc oxide nanorods (ZnO NRs) as a simple and low-cost fabrication material may fulfil the need as an ETL, but they still suffer from low PCE due to atomic defect vacancy. To delve into the issue, several dopants have been reviewed as an additive to passivate or substitute the Zn2+ vacancies, thus enhancing the charge transport mechanism. This work thereby unravels and provides a clear insight into dopant engineering in ZnO NRs ETL for PSC.
  10. Fulltext The frequency of pulmonary hypertension in newborn with intrauterine growth restriction
    Abbas G, Shah S, Hanif M, Shah A, Rehman AU, Tahir S, et al.
    Sci Rep, 2020 05 15;10(1):8064.
    PMID: 32415157 DOI: 10.1038/s41598-020-65065-2
    Intrauterine growth restriction (IUGR) is a clinical definition applied to neonates born with clinical features of malnutrition and in-utero growth retardation irrespective of their birth weight percentile. This study was aimed to determine the frequency of pulmonary hypertension (PH) in neonates with IUGR. In this descriptive cross-sectional study, we followed 96 neonates with IUGR (≤28 days) and 38 neonates without IUGR born in the department of the neonatal intensive care unit children hospital complex Multan, Pakistan. We analyzed certain factors such as gender, gestational age (GA) (weeks), birth weight (BW in kg), weight percentile (WP) for GA, meconium aspiration syndrome (MAS), birth asphyxia (BA) and respiratory distress syndrome (RDS) for pulmonary hypertension (PH) in IUGR and non-IUGR group. GA was measured by the Ballard scoring system. Echocardiography was performed for all patients by the pediatric cardiologist to measure pulmonary arterial (PA) pressure using Bernoulli's equation. Out of total 96 IUGR neonates, 33.3% (n = 32) suffered from PH, of which 65.3% (n = 18) were male and 43.7% (n = 14) were female. The percentages of IUGR neonates with BA, MAS and RDS were 34.4%, 18.8% and 22.9% respectively. The data were analyzed using the SPSS-16 software to test the statistical significance of the results. A p-value less than 0.05 was considered significant. When the chi-square test was applied, it depicted that MAS was significantly associated with PH in IUGR neonates (p = 0.0001) compared to non-IUGR neonates. Our findings suggested an increased chance of PH in IUGR neonates and MAS may be a strong factor.
  11. Fulltext Hospitalised patients' awareness of their rights: a cross-sectional survey from a tertiary care hospital on the east coast of Peninsular Malaysia
    Yousuf RM, Fauzi AR, How SH, Akter SF, Shah A
    Singapore Med J, 2009 May;50(5):494-9.
    PMID: 19495519
    Optimal patient care varies considerably from place to place and is influenced by scientific as well as social developments. The purpose of this study was to investigate awareness and pertinent issues regarding informed consent among hospitalised patients and to determine lapses, in order to improve the standard of care.
  12. A new sensitive electrochemical method for the determination of vanadium(IV) and vanadium(V) in Benfield sample
    Qureshi MS, Mohd Yusoff AR, Shah A, Nafady A, Sirajuddin
    Talanta, 2015 Jan;132:541-7.
    PMID: 25476342 DOI: 10.1016/j.talanta.2014.10.005
    Vanadium(IV) and vanadium(V) can be determined by using differential pulse cathodic stripping voltammetry technique (DPCSV). Cupferron (ammonium N-nitrosophenylhydroxylamine) was used as ligand to form complex compounds with vanadium ions in Britton-Robinson buffer (BRB) solution. At concentration lower than 1.0×10(-6) M, both V(IV) and V(V) cupferron complexes showed a single cathodic peak at -0.576 V in BRB of pH 4; thus V(IV) and V(V) ions cannot be differentiated at low concentration. However, the ionic species of vanadium can be differentiated at high concentration in the presence of cupferron. Parameters including pH of BRB solution, initial potential and accumulation potential were optimized. Under the optimized parameters, the limit of detection (LOD) was 0.09 nM, and the peak current was linear in the concentration range 0.01-0.9 µM total vanadium ions. The determination of V(IV) and V(V) ions was carried out at higher concentration in the sample using calibration plot method. At higher concentration range of 10-60 µM V(IV) and V(V) ions were determined with LOD of 1.2 and 1.1 µM, respectively. The developed method was successfully applied to 10,00,000 fold diluted Benfield sample and 0.6227 M total vanadium ions were determined. The determination of V(IV) and V(V) ions were also successfully carried out in artificial sample as well as Benfield sample (dilution factor, 10,000). The concentration of V(IV) and V(V) ions was 22.52 µM and 38.91 µM, respectively, giving total vanadium concentration of 0.6143 M in Benfield sample.
  13. High-Sensitivity Cardiac Troponin I Levels in Normal and Hypertensive Pregnancy
    Ravichandran J, Woon SY, Quek YS, Lim YC, Noor EM, Suresh K, et al.
    Am J Med, 2019 03;132(3):362-366.
    PMID: 30503877 DOI: 10.1016/j.amjmed.2018.11.017
    PURPOSE: The purpose of this study was to examine the association of circulating concentrations of high-sensitivity cardiac troponin I (hs-cTn) in the various trimesters of pregnancy in patients with and without hypertension.

    METHODS: This was a prospective cross-sectional study of pregnant and postnatal women aged between 18-35 years with no coexisting diseases. Serum samples were analysed for hs-TnI.

    RESULTS: A total of 880 women (mean age = 29.1 years [standard deviation = 5.1 years]) were recruited with 129 (14%), 207 (24%), and 416 (47%) patients in the first, second, and third trimesters, respectively. Ninety (10%) participants were recruited in the postnatal period. During pregnancy 28 (3%) patients were classified as having pregnancy-induced hypertension and 10 (1%) as preeclampsia. High-sensitivity cardiac troponin I was measurable in 546 (62%) participants with a median of 1 ng/L (range 0 to 783 ng/L). Troponin concentrations were above the 99th percentile in 19 (2%) individuals. Patients with pregnancy-induced hypertension and preeclampsia had higher concentrations of hs-TnI (median 11 ng/L [interquartile range (IQR) 6 to 22 ng/L] vs 12ng/L [IQR 3 to 98 ng/L] vs 1 ng/L [IQR 0 to 1 ng/L]). In logistic regression modeling hs-cTnI concentration remained an independent predictor of pregnancy-induced hypertension or preeclampsia in both unadjusted and adjusted models (odds ratio 9.3 [95% confidence interval 5.8 to 16.3] and 11.5 [95% confidence interval 6.3 to 24.1], respectively, per doubling of hs-TnI concentrations).

    CONCLUSIONS: Cardiac troponin measured using a high-sensitivity assay is quantifiable in the majority of young pregnant women with 2% of individuals having concentration above the 99th percentile sex-specific threshold. Patients with pregnancy-induced hypertension or preeclampsia had higher cardiac troponin concentrations. Cardiac troponin was a strong independent predictor of pregnancy-induced hypertension or preeclampsia in pregnant and postnatal women.

  14. Fulltext Search for supersymmetry in events with a photon, jets, b -jets, and missing transverse momentum in proton-proton collisions at 13 Te
    Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Asilar E, Bergauer T, et al.
    Eur Phys J C Part Fields, 2019;79(5):444.
    PMID: 31265003 DOI: 10.1140/epjc/s10052-019-6926-x
    A search for supersymmetry is presented based on events with at least one photon, jets, and large missing transverse momentum produced in proton-proton collisions at a center-of-mass energy of 13



    Te



    . The data correspond to an integrated luminosity of 35.9



    fb

    -
    1



    and were recorded at the LHC with the CMS detector in 2016. The analysis characterizes signal-like events by categorizing the data into various signal regions based on the number of jets, the number of
    b
    -tagged jets, and the missing transverse momentum. No significant excess of events is observed with respect to the expectations from standard model processes. Limits are placed on the gluino and top squark pair production cross sections using several simplified models of supersymmetric particle production with gauge-mediated supersymmetry breaking. Depending on the model and the mass of the next-to-lightest supersymmetric particle, the production of gluinos with masses as large as 2120



    Ge



    and the production of top squarks with masses as large as 1230



    Ge



    are excluded at 95% confidence level.
  15. Search for single production of vector-like quarks decaying to a top quark and a W boson in proton-proton collisions at s = 13 TeV
    Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Asilar E, Bergauer T, et al.
    Eur Phys J C Part Fields, 2019;79(2):90.
    PMID: 30814908 DOI: 10.1140/epjc/s10052-019-6556-3
    A search is presented for the single production of vector-like quarks in proton-proton collisions at


    s

    =
    13

    TeV

    . The data, corresponding to an integrated luminosity of 35.9



    fb

    -
    1



    , were recorded with the CMS experiment at the LHC. The analysis focuses on the vector-like quark decay into a top quark and a
    W
    boson, with one muon or electron in the final state. The mass of the vector-like quark candidate is reconstructed from hadronic jets, the lepton, and the missing transverse momentum. Methods for the identification of
    b
    quarks and of highly Lorentz boosted hadronically decaying top quarks and
    W
    bosons are exploited in this search. No significant deviation from the standard model background expectation is observed. Exclusion limits at 95% confidence level are set on the product of the production cross section and branching fraction as a function of the vector-like quark mass, which range from 0.3 to 0.03


    pb

    for vector-like quark masses of 700 to 2000


    GeV

    . Mass exclusion limits up to 1660


    GeV

    are obtained, depending on the vector-like quark type, coupling, and decay width. These represent the most stringent exclusion limits for the single production of vector-like quarks in this channel.
  16. Fulltext Measurements of triple-differential cross sections for inclusive isolated-photon+jet events in p p collisions at s = 8 TeV
    Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Asilar E, Bergauer T, et al.
    Eur Phys J C Part Fields, 2019;79(11):969.
    PMID: 31886778 DOI: 10.1140/epjc/s10052-019-7451-7
    Measurements are presented of the triple-differential cross section for inclusive isolated-photon+jet events in

    p
    p

    collisions at


    s

    =
    8

    TeV as a function of photon transverse momentum (

    p

    T


    γ




    ), photon pseudorapidity (

    η

    γ




    ), and jet pseudorapidity (

    η
    jet

    ). The data correspond to an integrated luminosity of

    19.7



    fb

    -
    1




    that probe a broad range of the available phase space, for


    |


    η

    γ





    |
    <
    1.44


    and


    1.57
    <
    |


    η

    γ





    |
    <
    2.50


    ,


    |


    η
    jet


    |
    <
    2.5


    ,

    40
    <

    p

    T


    γ




    <
    1000




    GeV

    , and jet transverse momentum,

    p

    T

    jet

    , > 25


    GeV

    . The measurements are compared to next-to-leading order perturbative quantum chromodynamics calculations, which reproduce the data within uncertainties.
  17. Fulltext Search for dark matter produced in association with heavy-flavor quark pairs in proton-proton collisions at s = 13 TeV
    Sirunyan AM, Tumasyan A, Adam W, Asilar E, Bergauer T, Brandstetter J, et al.
    Eur Phys J C Part Fields, 2017;77(12):845.
    PMID: 31985736 DOI: 10.1140/epjc/s10052-017-5317-4
    A search is presented for an excess of events with heavy-flavor quark pairs (

    t

    t
    ¯


    and

    b

    b
    ¯


    ) and a large imbalance in transverse momentum in data from proton-proton collisions at a center-of-mass energy of 13


    TeV

    . The data correspond to an integrated luminosity of 2.2



    fb

    -
    1



    collected with the CMS detector at the CERN LHC. No deviations are observed with respect to standard model predictions. The results are used in the first interpretation of dark matter production in

    t

    t
    ¯


    and

    b

    b
    ¯


    final states in a simplified model. This analysis is also the first to perform a statistical combination of searches for dark matter produced with different heavy-flavor final states. The combination provides exclusions that are stronger than those achieved with individual heavy-flavor final states.
  18. Fulltext Development and validation of HERWIG 7 tunes from CMS underlying-event measurements
    Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Bergauer T, Dragicevic M, et al.
    Eur Phys J C Part Fields, 2021;81(4):312.
    PMID: 34727148 DOI: 10.1140/epjc/s10052-021-08949-5
    This paper presents new sets of parameters ("tunes") for the underlying-event model of the H E R W I G 7 event generator. These parameters control the description of multiple-parton interactions (MPI) and colour reconnection in H E R W I G 7 , and are obtained from a fit to minimum-bias data collected by the CMS experiment at s = 0.9 , 7, and 13 Te . 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 data.
  19. Fulltext MUSiC: a model-unspecific search for new physics in proton-proton collisions at s = 13 TeV
    CMS Collaboration, Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Bergauer T, et al.
    Eur Phys J C Part Fields, 2021;81(7):629.
    PMID: 34727144 DOI: 10.1140/epjc/s10052-021-09236-z
    Results of the Model Unspecific Search in CMS (MUSiC), using proton-proton collision data recorded at the LHC at a centre-of-mass energy of 13 TeV , corresponding to an integrated luminosity of 35.9 fb - 1 , are presented. The MUSiC analysis searches for anomalies that could be signatures of physics beyond the standard model. The analysis is based on the comparison of observed data with the standard model prediction, as determined from simulation, in several hundred final states and multiple kinematic distributions. Events containing at least one electron or muon are classified based on their final state topology, and an automated search algorithm surveys the observed data for deviations from the prediction. The sensitivity of the search is validated using multiple methods. No significant deviations from the predictions have been observed. For a wide range of final state topologies, agreement is found between the data and the standard model simulation. This analysis complements dedicated search analyses by significantly expanding the range of final states covered using a model independent approach with the largest data set to date to probe phase space regions beyond the reach of previous general searches.
  20. Fulltext Combined searches for the production of supersymmetric top quark partners in proton-proton collisions at s = 13 Te
    Tumasyan A, Adam W, Andrejkovic JW, Bergauer T, Chatterjee S, Dragicevic M, et al.
    Eur Phys J C Part Fields, 2021;81(11):970.
    PMID: 34793584 DOI: 10.1140/epjc/s10052-021-09721-5
    A combination of searches for top squark pair production using proton-proton collision data at a center-of-mass energy of 13 Te at the CERN LHC, corresponding to an integrated luminosity of 137 fb - 1 collected by the CMS experiment, is presented. Signatures with at least 2 jets and large missing transverse momentum are categorized into events with 0, 1, or 2 leptons. New results for regions of parameter space where the kinematical properties of top squark pair production and top quark pair production are very similar are presented. Depending on the model, the combined result excludes a top squark mass up to 1325 Ge for a massless neutralino, and a neutralino mass up to 700 Ge for a top squark mass of 1150 Ge . Top squarks with masses from 145 to 295 Ge , for neutralino masses from 0 to 100 Ge , with a mass difference between the top squark and the neutralino in a window of 30 Ge around the mass of the top quark, are excluded for the first time with CMS data. The results of theses searches are also interpreted in an alternative signal model of dark matter production via a spin-0 mediator in association with a top quark pair. Upper limits are set on the cross section for mediator particle masses of up to 420 Ge .
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