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  1. Fulltext Psychometric Properties of the Self-Efficacy Scale among Undergraduate Students in Malaysia
    Ting LK, Kuan G, Arifin WN, Cheng KY
    Malays J Med Sci, 2019 May;26(3):119-128.
    PMID: 31303856 MyJurnal DOI: 10.21315/mjms2019.26.3.10
    Background: Self-efficacy (SE) is a person's belief in his or her own capability to perform and accomplish a task that could produce a favourable outcome, despite facing obstacles. This study aimed to confirm the validity and reliability of an SE scale among undergraduate students at the Health Campus of the Universiti Sains Malaysia.

    Methods: A cross-sectional study was conducted among the undergraduate students using a self-administered questionnaire. After using a purposive sampling method, 562 students completed the questionnaire. Mplus 8 was employed to conduct the confirmatory factor analysis on the psychometric properties of Bandura's 18-item SE scale with three factors (internal feeling, competing demands and situational). Then, the composite reliability was calculated for each factor.

    Results: Most of the students were Malay (73.3%) females (79.0%) who exercised 2.62 times a week for an average of 43.37 min per session. The final measurement model was obtained after removing six problematic items, and the model was deemed fit based on several indices [Root Mean Square Error of Approximation (RMSEA) = 0.067, Standardised Root Mean Square Residual (SRMR) = 0.004, Comparative Fit Index (CFI) = 0.924]. The composite reliability values of the three factors were acceptable (0.65 to 0.84).

    Conclusion: The simplified 12-item SE scale with three factors displayed good fit indices with regard to the data, and they were considered to be acceptable for the current sample.

  2. Fulltext Validation of the malay version of the Affiliate Stigma Scale among caregivers of patients with mental illness
    Yun YS, Jaapar SZS, Fadzil NA, Cheng KY
    Malays J Med Sci, 2018 Nov;25(6):127-136.
    PMID: 30914886 MyJurnal DOI: 10.21315/mjms2018.25.6.13
    Background: Caregivers of patients with mental illness are exposed to stigma. The internalisation of this stigma among caregivers is known as affiliate stigma and can be measured by the Affiliate Stigma Scale (ASS). The aim of this study was to validate the Malay version of the ASS.
    Methods: A cross-sectional study was performed from May to December 2017 with 372 caregivers of patients with mental illness. The ASS was first translated into Malay using standard forward and backward translation procedures. The final version of the ASS-Malay (ASS-M) was completed by participants. The data analyses involved assessment of construct validity by exploratory factor analysis, confirmatory factor analysis and construct reliability.
    Results: The final model of the ASS-M consists of four factors with 21 items, as compared to the original version, which has three factors with 22 items. The results showed that the final model has good model fit based on RMSEA (0.065) and SRMR (0.055) and a satisfactory composite reliability (affective = 0.827, cognitive = 0.857, behaviour = 0.764, self-esteem = 0.861).
    Conclusion: The study showed that the four-factor, 21-item ASS-M model has good psychometric properties. The scale is valid and reliable for measuring affiliate stigma among caregivers of patients with mental illness in Malaysia.
  3. Fulltext The Incontinence Praying Ability and the Incontinence Quality of Life Questionnaires for Muslim Women: A Confirmatory Study of the Malay Language Versions
    Cheng KY, Yusoff DM, Ismail H, Naing NN
    Malays J Med Sci, 2018 Sep;25(5):115-127.
    PMID: 30914868 MyJurnal DOI: 10.21315/mjms2018.25.5.11
    BACKGROUND: The aim of the present study was to determine the validity and reliability of the Malay versions of the Incontinence Praying Ability (I-PA) and the Incontinence Quality of Life (I-QoL) questionnaires among childbearing-aged Muslim women.

    METHODS: This cross-sectional study included 338 childbearing-aged Muslim women (mean age: 31.1 years; SD = 5.57) who attended clinics at Hospital Universiti Sains Malaysia. Confirmatory factor analysis was conducted to determine the construct validity of the Malay versions of the I-PA and the I-QoL, while composite reliability was used to examine their internal consistency reliability.

    RESULTS: The hypothesised models of the I-PA and the I-QoL consisted of 10 items with one latent variable and 22 items with three latent variables, respectively. The hypothesised models of the I-PA and the I-QoL did not have good fit. Modifications included co-varying the residual terms for items within the subscales, which resulted in improved fit indices for the I-PA (CFI = 0.976 TLI = 0.961, RMSEA = 0.068) and the I-QoL (CFI = 0.948, TLI = 0.938, RMSEA = 0.063). The composite reliability of the I-PA was 0.93, and the I-QoL ranged from 0.91 to 0.94.

    CONCLUSION: The Malay versions of the I-PA and I-QoL were considered to be valid, reliable questionnaires measuring incontinence QoL among Muslim women of childbearing age.

  4. Fulltext Constructing causal pathways for premature cardiovascular disease mortality using directed acyclic graphs with integrating evidence synthesis and expert knowledge
    Hasani WSR, Musa KI, Chen XW, Cheng KY
    Sci Rep, 2024 Nov 21;14(1):28849.
    PMID: 39572630 DOI: 10.1038/s41598-024-80091-0
    Cardiovascular disease (CVD) is a major global cause of premature mortality. While multiple studies propose CVD mortality prediction models based on regression frameworks, incorporating causal understanding through causal inference approaches can enhance accuracy. This paper demonstrates a methodology combining evidence synthesis and expert knowledge to construct a causal model for premature CVD mortality using Directed Acyclic Graphs (DAGs). The process involves three phases: (1) initial DAG development based on the Evidence Synthesis for Constructing Directed Acyclic Graphs (ESC-DAGs) framework, (2) validation and consensus-building with 12 experts using the Fuzzy Delphi method (FDM), and (3) application to data analysis using population-based survey data linked with death records. Expert input refined the initial DAG model, achieving consensus on 45 causal paths. The revised model guided selection of confounding variables for adjustment. For example, to estimate the total effect of diabetes on premature CVD mortality, the suggested adjustment set included age, dietary pattern, genetic/family history, sex hormones, and physical activity. Testing different DAG models showed agreement between expert ratings and data accuracy from regression models. This systematic approach contributes to DAG methodology, offering a transparent process for constructing causal pathways for premature CVD mortality.
  5. Career Intentions and the Determining Factors among Health Science Students: A Systematic Review
    Stanley N, Binti Bakar RS, Cheng KY, Nwedu AB, Binti Hassan II
    Creat Nurs, 2023 Feb;29(1):65-97.
    PMID: 37551007 DOI: 10.1177/107845352202900113
    BACKGROUND: Health systemsneed adequate personnelin order to function; improvements in health-care services delivery, and coverage and the enjoyment of standard healthcare as a right, depend on the availability, mixture, quality, and accessibility of the health-care workforce.

    PURPOSE: This review aimed to synthesize reliable evidence ondetermining factors among health science students' career choices to enhance policy advocacy for better health-care delivery.

    METHOD: We sourced empirical studies from Scopus, PubMed, ScienceDirect and Google Scholar. From a total of 9,056 researcharticlesfrom 2010 to 2022, 27 studies with a total of 45,832 respondents met the inclusion criteria.

    RESULTS: The majority of the studies were of medical students; internal medicine was the commonest choice (64.3%), with psychiatry and public health receiving lesser attention. In the four available studies of nursing students, midwifery was not chosen at all. There is a paucity of studies on this all-important concept for nursing students. The determining factors of choice of specialty were in four themes: personal, socioeconomic, professional, and educational/policy. Among the barriers to choosing particular specialties were low prestige among colleagues, stigma, long working hours, and poor public recognition.

    CONCLUSION: The career choices of health science students do not reflect an adequate mix of health-care team members to meet the health-care needs of the world. Reforms of policy and educational training are needed.

  6. Impacts of clinical psychiatric posting experience on specialization intention and associated factors among Nursing Science students
    Njaka S, Hassan IIB, Nwedu AB, Bakar RSB, Cheng KY
    BMC Nurs, 2024 Sep 10;23(1):630.
    PMID: 39256707 DOI: 10.1186/s12912-024-02298-w
    BACKGROUND: Globally, there is increasingly high prevalence of mental disorders across all age groups and social classes with more being projected by 2030, but without commensurate resources for mental health care delivery especially in developing countries.

    PURPOSE: This study examined the impacts of clinical psychiatric posting on career choice in psychiatry among nursing students in Ebonyi state, Nigeria.

    METHODS: A prospective cohort research design was used and data were collected using attitude towards psychiatry (ATP), mental illness clinician attitude scale (MICA-4) and researcher developed questionnaires on career choice in pre and post clinical posting approach. This study was conducted between November, 2023 to May 2024. A sample size of 400 students (with data collected before posting and after posting) were involved in the study. Data were coded, cleaned and analyzed using SPSS version 26. McNemar Test was used to determine effects of clinical posting on career choices in psychiatry. Simple and multiple logistic regressions were used to analyze data on determinants of career choices in psychiatry. The hypotheses (Null and alternative hypotheses) were tested at p-value 

  7. Studies of Charm Quark Diffusion inside Jets Using Pb-Pb and pp Collisions at sqrt[s_{NN}]=5.02  TeV
    Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Asilar E, Bergauer T, et al.
    Phys Rev Lett, 2020 Sep 04;125(10):102001.
    PMID: 32955327 DOI: 10.1103/PhysRevLett.125.102001
    The first study of charm quark diffusion with respect to the jet axis in heavy ion collisions is presented. The measurement is performed using jets with p_{T}^{jet}>60  GeV/c and D^{0} mesons with p_{T}^{D}>4  GeV/c in lead-lead (Pb-Pb) and proton-proton (pp) collisions at a nucleon-nucleon center-of-mass energy of sqrt[s_{NN}]=5.02  TeV, recorded by the CMS detector at the LHC. The radial distribution of D^{0} mesons with respect to the jet axis is sensitive to the production mechanisms of the meson, as well as to the energy loss and diffusion processes undergone by its parent parton inside the strongly interacting medium produced in Pb-Pb collisions. When compared to Monte Carlo event generators, the radial distribution in pp collisions is found to be well described by pythia, while the slope of the distribution predicted by sherpa is steeper than that of the data. In Pb-Pb collisions, compared to the pp results, the D^{0} meson distribution for 4
  8. Search for the X(5568) State Decaying into B_{s}^{0}π^{±} in Proton-Proton Collisions at sqrt[s]=8  TeV
    Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Asilar E, Bergauer T, et al.
    Phys Rev Lett, 2018 May 18;120(20):202005.
    PMID: 29864318 DOI: 10.1103/PhysRevLett.120.202005
    A search for resonancelike structures in the B_{s}^{0}π^{±} invariant mass spectrum is performed using proton-proton collision data collected by the CMS experiment at the LHC at sqrt[s]=8  TeV, corresponding to an integrated luminosity of 19.7  fb^{-1}. The B_{s}^{0} mesons are reconstructed in the decay chain B_{s}^{0}→J/ψϕ, with J/ψ→μ^{+}μ^{-} and ϕ→K^{+}K^{-}. The B_{s}^{0}π^{±} invariant mass distribution shows no statistically significant peaks for different selection requirements on the reconstructed B_{s}^{0} and π^{±} candidates. Upper limits are set on the relative production rates of the X(5568) and B_{s}^{0} states times the branching fraction of the decay X(5568)^{±}→B_{s}^{0}π^{±}. In addition, upper limits are obtained as a function of the mass and the natural width of possible exotic states decaying into B_{s}^{0}π^{±}.
  9. Search for Narrow Resonances in the b-Tagged Dijet Mass Spectrum in Proton-Proton Collisions at sqrt[s]=8  TeV
    Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Asilar E, Bergauer T, et al.
    Phys Rev Lett, 2018 May 18;120(20):201801.
    PMID: 29864370 DOI: 10.1103/PhysRevLett.120.201801
    A search for narrow resonances decaying to bottom quark-antiquark pairs is presented, using a data sample of proton-proton collisions at sqrt[s]=8  TeV corresponding to an integrated luminosity of 19.7  fb^{-1}. The search is extended to masses lower than those reached in typical searches for resonances decaying into jet pairs at the LHC, by taking advantage of triggers that identify jets originating from bottom quarks. No significant excess of events is observed above the background predictions. Limits are set on the product of cross section and branching fraction to bottom quarks for spin 0, 1, and 2 resonances in the mass range of 325-1200 GeV. These results improve on the limits for resonances decaying into jet pairs in the 325-500 GeV mass range.
  10. Search for Leptoquarks Coupled to Third-Generation Quarks in Proton-Proton Collisions at sqrt[s]=13  TeV
    Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Asilar E, Bergauer T, et al.
    Phys Rev Lett, 2018 Dec 14;121(24):241802.
    PMID: 30608761 DOI: 10.1103/PhysRevLett.121.241802
    Three of the most significant measured deviations from standard model predictions, the enhanced decay rate for B→D^{(*)}τν, hints of lepton universality violation in B→K^{(*)}ℓℓ decays, and the anomalous magnetic moment of the muon, can be explained by the existence of leptoquarks (LQs) with large couplings to third-generation quarks and masses at the TeV scale. The existence of these states can be probed at the LHC in high energy proton-proton collisions. A novel search is presented for pair production of LQs coupled to a top quark and a muon using data at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9  fb^{-1}, recorded by the CMS experiment. No deviation from the standard model prediction has been observed and scalar LQs decaying exclusively into tμ are excluded up to masses of 1420 GeV. The results of this search are combined with those from previous searches for LQ decays into tτ and bν, which excluded scalar LQs below masses of 900 and 1080 GeV. Vector LQs are excluded up to masses of 1190 GeV for all possible combinations of branching fractions to tμ, tτ and bν. With this analysis, all relevant couplings of LQs with an electric charge of -1/3 to third-generation quarks are probed for the first time.
  11. Observation of Medium-Induced Modifications of Jet Fragmentation in Pb-Pb Collisions at sqrt[s_{NN}]=5.02  TeV Using Isolated Photon-Tagged Jets
    Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Asilar E, Bergauer T, et al.
    Phys Rev Lett, 2018 Dec 14;121(24):242301.
    PMID: 30608764 DOI: 10.1103/PhysRevLett.121.242301
    Measurements of fragmentation functions for jets associated with an isolated photon are presented for the first time in pp and Pb-Pb collisions. The analysis uses data collected with the CMS detector at the CERN LHC at a nucleon-nucleon center-of-mass energy of 5.02 TeV. Fragmentation functions are obtained for jets with p_{T}^{jet}>30  GeV/c in events containing an isolated photon with p_{T}^{γ}>60  GeV/c, using charged tracks with transverse momentum p_{T}^{trk}>1  GeV/c in a cone around the jet axis. The association with an isolated photon constrains the initial p_{T} and azimuthal angle of the parton whose shower produced the jet. For central Pb-Pb collisions, modifications of the jet fragmentation functions are observed when compared to those measured in pp collisions, while no significant differences are found in the 50% most peripheral collisions. Jets in central Pb-Pb events show an excess (depletion) of low (high) p_{T} particles, with a transition around 3  GeV/c. This measurement shows for the first time the in-medium shower modifications of partons (quark dominated) with well-defined initial kinematics. It constitutes a new well-controlled reference for testing theoretical models of the parton passage through the quark-gluon plasma.
  12. Evidence for the Associated Production of a Single Top Quark and a Photon in Proton-Proton Collisions at sqrt[s]=13  TeV
    Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Asilar E, Bergauer T, et al.
    Phys Rev Lett, 2018 Nov 30;121(22):221802.
    PMID: 30547617 DOI: 10.1103/PhysRevLett.121.221802
    The first evidence of events consistent with the production of a single top quark in association with a photon is reported. The analysis is based on proton-proton collisions at sqrt[s]=13  TeV and recorded by the CMS experiment in 2016, corresponding to an integrated luminosity of 35.9  fb^{-1}. Events are selected by requiring the presence of a muon (μ), a photon (γ), an imbalance in transverse momentum from an undetected neutrino (ν), and at least two jets (j) of which exactly one is identified as associated with the hadronization of a b quark. A multivariate discriminant based on topological and kinematic event properties is employed to separate signal from background processes. An excess above the background-only hypothesis is observed, with a significance of 4.4 standard deviations. A fiducial cross section is measured for isolated photons with transverse momentum greater than 25 GeV in the central region of the detector. The measured product of the cross section and branching fraction is σ(pp→tγj)B(t→μνb)=115±17(stat)±30(syst)  fb, which is consistent with the standard model prediction.
  13. Studies of Beauty Suppression via Nonprompt D^{0} Mesons in Pb-Pb Collisions at sqrt[s_{NN}]=5.02  TeV
    Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Asilar E, Bergauer T, et al.
    Phys Rev Lett, 2019 Jul 12;123(2):022001.
    PMID: 31386524 DOI: 10.1103/PhysRevLett.123.022001
    The transverse momentum spectra of D^{0} mesons from b hadron decays are measured at midrapidity (|y|<1) in pp and Pb-Pb collisions at a nucleon-nucleon center of mass energy of 5.02 TeV with the CMS detector at the LHC. The D^{0} mesons from b hadron decays are distinguished from prompt D^{0} mesons by their decay topologies. In Pb-Pb collisions, the B→D^{0} yield is found to be suppressed in the measured p_{T} range from 2 to 100  GeV/c as compared to pp collisions. The suppression is weaker than that of prompt D^{0} mesons and charged hadrons for p_{T} around 10  GeV/c. While theoretical calculations incorporating partonic energy loss in the quark-gluon plasma can successfully describe the measured B→D^{0} suppression at higher p_{T}, the data show an indication of larger suppression than the model predictions in the range of 2
  14. Jet Shapes of Isolated Photon-Tagged Jets in Pb-Pb and pp Collisions at sqrt[s_{NN}]=5.02  TeV
    Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Asilar E, Bergauer T, et al.
    Phys Rev Lett, 2019 Apr 19;122(15):152001.
    PMID: 31050516 DOI: 10.1103/PhysRevLett.122.152001
    The modification of jet shapes in Pb-Pb collisions, relative to those in pp collisions, is studied for jets associated with an isolated photon. The data were collected with the CMS detector at the LHC at a nucleon-nucleon center-of-mass energy of 5.02 TeV. Jet shapes are constructed from charged particles with track transverse momenta (p_{T}) above 1  GeV/c in annuli around the axes of jets with p_{T}^{jet}>30  GeV/c associated with an isolated photon with p_{T}^{γ}>60  GeV/c. The jet shape distributions are consistent between peripheral Pb-Pb and pp collisions, but are modified for more central Pb-Pb collisions. In these central Pb-Pb events, a larger fraction of the jet momentum is observed at larger distances from the jet axis compared to pp, reflecting the interaction between the partonic medium created in heavy ion collisions and the traversing partons.
  15. Search for Narrow Hγ Resonances in Proton-Proton Collisions at sqrt[s]=13  TeV
    Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Asilar E, Bergauer T, et al.
    Phys Rev Lett, 2019 Mar 01;122(8):081804.
    PMID: 30932612 DOI: 10.1103/PhysRevLett.122.081804
    A search for heavy, narrow resonances decaying to a Higgs boson and a photon (Hγ) has been performed in proton-proton collision data at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9  fb^{-1} collected with the CMS detector at the LHC in 2016. Events containing a photon and a Lorentz-boosted hadronically decaying Higgs boson reconstructed as a single, large-radius jet are considered, and the γ+jet invariant mass spectrum is analyzed for the presence of narrow resonances. To increase the sensitivity of the search, events are categorized depending on whether or not the large-radius jet can be identified as a result of the merging of two jets originating from b quarks. Results in both categories are found to agree with the predictions of the standard model. Upper limits on the production rate of Hγ resonances are set as a function of their mass in the range of 720-3250 GeV, representing the most stringent constraints to date.
  16. Search for Dark Matter Particles Produced in Association with a Top Quark Pair at sqrt[s]=13  TeV
    Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Asilar E, Bergauer T, et al.
    Phys Rev Lett, 2019 Jan 11;122(1):011803.
    PMID: 31012697 DOI: 10.1103/PhysRevLett.122.011803
    A search is performed for dark matter particles produced in association with a top quark pair in proton-proton collisions at sqrt[s]=13  TeV. The data correspond to an integrated luminosity of 35.9  fb^{-1} recorded by the CMS detector at the LHC. No significant excess over the standard model expectation is observed. The results are interpreted using simplified models of dark matter production via spin-0 mediators that couple to dark matter particles and to standard model quarks, providing constraints on the coupling strength between the mediator and the quarks. These are the most stringent collider limits to date for scalar mediators, and the most stringent for pseudoscalar mediators at low masses.
  17. Search for Physics Beyond the Standard Model in Events with High-Momentum Higgs Bosons and Missing Transverse Momentum in Proton-Proton Collisions at 13 TeV
    Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Asilar E, Bergauer T, et al.
    Phys Rev Lett, 2018 Jun 15;120(24):241801.
    PMID: 29956995 DOI: 10.1103/PhysRevLett.120.241801
    A search for physics beyond the standard model in events with one or more high-momentum Higgs bosons, H, decaying to pairs of b quarks in association with missing transverse momentum is presented. The data, corresponding to an integrated luminosity of 35.9  fb^{-1}, were collected with the CMS detector at the LHC in proton-proton collisions at the center-of-mass energy sqrt[s]=13  TeV. The analysis utilizes a new b quark tagging technique based on jet substructure to identify jets from H→bb[over ¯]. Events are categorized by the multiplicity of H-tagged jets, jet mass, and the missing transverse momentum. No significant deviation from standard model expectations is observed. In the context of supersymmetry (SUSY), limits on the cross sections of pair-produced gluinos are set, assuming that gluinos decay to quark pairs, H (or Z), and the lightest SUSY particle, LSP, through an intermediate next-to-lightest SUSY particle, NLSP. With large mass splitting between the NLSP and LSP, and 100% NLSP branching fraction to H, the lower limit on the gluino mass is found to be 2010 GeV.
  18. Observation of tt[over ¯]H Production
    Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Asilar E, Bergauer T, et al.
    Phys Rev Lett, 2018 Jun 08;120(23):231801.
    PMID: 29932697 DOI: 10.1103/PhysRevLett.120.231801
    The observation of Higgs boson production in association with a top quark-antiquark pair is reported, based on a combined analysis of proton-proton collision data at center-of-mass energies of sqrt[s]=7, 8, and 13 TeV, corresponding to integrated luminosities of up to 5.1, 19.7, and 35.9  fb^{-1}, respectively. The data were collected with the CMS detector at the CERN LHC. The results of statistically independent searches for Higgs bosons produced in conjunction with a top quark-antiquark pair and decaying to pairs of W bosons, Z bosons, photons, τ leptons, or bottom quark jets are combined to maximize sensitivity. An excess of events is observed, with a significance of 5.2 standard deviations, over the expectation from the background-only hypothesis. The corresponding expected significance from the standard model for a Higgs boson mass of 125.09 GeV is 4.2 standard deviations. The combined best fit signal strength normalized to the standard model prediction is 1.26_{-0.26}^{+0.31}.
  19. Search for Heavy Neutral Leptons in Events with Three Charged Leptons in Proton-Proton Collisions at sqrt[s]=13  TeV
    Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Asilar E, Bergauer T, et al.
    Phys Rev Lett, 2018 Jun 01;120(22):221801.
    PMID: 29906166 DOI: 10.1103/PhysRevLett.120.221801
    A search for a heavy neutral lepton N of Majorana nature decaying into a W boson and a charged lepton is performed using the CMS detector at the LHC. The targeted signature consists of three prompt charged leptons in any flavor combination of electrons and muons. The data were collected in proton-proton collisions at a center-of-mass energy of 13 TeV, with an integrated luminosity of 35.9  fb^{-1}. The search is performed in the N mass range between 1 GeV and 1.2 TeV. The data are found to be consistent with the expected standard model background. Upper limits are set on the values of |V_{eN}|^{2} and |V_{μN}|^{2}, where V_{ℓN} is the matrix element describing the mixing of N with the standard model neutrino of flavor ℓ. These are the first direct limits for N masses above 500 GeV and the first limits obtained at a hadron collider for N masses below 40 GeV.
  20. Observation of the χ_{b1}(3P) and χ_{b2}(3P) and Measurement of their Masses
    Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Asilar E, Bergauer T, et al.
    Phys Rev Lett, 2018 Aug 31;121(9):092002.
    PMID: 30230889 DOI: 10.1103/PhysRevLett.121.092002
    The χ_{b1}(3P) and χ_{b2}(3P) states are observed through their ϒ(3S)γ decays, using an event sample of proton-proton collisions collected by the CMS experiment at the CERN LHC. The data were collected at a center-of-mass energy of 13 TeV and correspond to an integrated luminosity of 80.0  fb^{-1}. The ϒ(3S) mesons are identified through their dimuon decay channel, while the low-energy photons are detected after converting to e^{+}e^{-} pairs in the silicon tracker, leading to a χ_{b}(3P) mass resolution of 2.2 MeV. This is the first time that the J=1 and 2 states are well resolved and their masses individually measured: 10513.42±0.41(stat)±0.18(syst)  MeV and 10524.02±0.57(stat)±0.18(syst)  MeV; they are determined with respect to the world-average value of the ϒ(3S) mass, which has an uncertainty of 0.5 MeV. The mass splitting is measured to be 10.60±0.64(stat)±0.17(syst)  MeV.
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