Displaying publications 1 - 20 of 114 in total

Abstract:
Sort:
  1. Zhou XD, Targher G, Byrne CD, Somers V, Kim SU, Chahal CAA, et al.
    Hepatol Int, 2023 Aug;17(4):773-791.
    PMID: 37204656 DOI: 10.1007/s12072-023-10543-8
    BACKGROUND: Fatty liver disease in the absence of excessive alcohol consumption is an increasingly common condition with a global prevalence of ~ 25-30% and is also associated with cardiovascular disease (CVD). Since systemic metabolic dysfunction underlies its pathogenesis, the term metabolic (dysfunction)-associated fatty liver disease (MAFLD) has been proposed for this condition. MAFLD is closely intertwined with obesity, type 2 diabetes mellitus and atherogenic dyslipidemia, which are established cardiovascular risk factors. Unlike CVD, which has received attention in the literature on fatty liver disease, the CVD risk associated with MAFLD is often underestimated, especially among Cardiologists.

    METHODS AND RESULTS: A multidisciplinary panel of fifty-two international experts comprising Hepatologists, Endocrinologists, Diabetologists, Cardiologists and Family Physicians from six continents (Asia, Europe, North America, South America, Africa and Oceania) participated in a formal Delphi survey and developed consensus statements on the association between MAFLD and the risk of CVD. Statements were developed on different aspects of CVD risk, ranging from epidemiology to mechanisms, screening, and management.

    CONCULSIONS: The expert panel identified important clinical associations between MAFLD and the risk of CVD that could serve to increase awareness of the adverse metabolic and cardiovascular outcomes of MAFLD. Finally, the expert panel also suggests potential areas for future research.

  2. Zhang H, Rios RS, Boursier J, Anty R, Chan WK, George J, et al.
    Chin Med J (Engl), 2023 Feb 05;136(3):341-350.
    PMID: 36848175 DOI: 10.1097/CM9.0000000000002603
    BACKGROUND: Liver biopsy for the diagnosis of non-alcoholic steatohepatitis (NASH) is limited by its inherent invasiveness and possible sampling errors. Some studies have shown that cytokeratin-18 (CK-18) concentrations may be useful in diagnosing NASH, but results across studies have been inconsistent. We aimed to identify the utility of CK-18 M30 concentrations as an alternative to liver biopsy for non-invasive identification of NASH.

    METHODS: Individual data were collected from 14 registry centers on patients with biopsy-proven non-alcoholic fatty liver disease (NAFLD), and in all patients, circulating CK-18 M30 levels were measured. Individuals with a NAFLD activity score (NAS) ≥5 with a score of ≥1 for each of steatosis, ballooning, and lobular inflammation were diagnosed as having definite NASH; individuals with a NAS ≤2 and no fibrosis were diagnosed as having non-alcoholic fatty liver (NAFL).

    RESULTS: A total of 2571 participants were screened, and 1008 (153 with NAFL and 855 with NASH) were finally enrolled. Median CK-18 M30 levels were higher in patients with NASH than in those with NAFL (mean difference 177 U/L; standardized mean difference [SMD]: 0.87 [0.69-1.04]). There was an interaction between CK-18 M30 levels and serum alanine aminotransferase, body mass index (BMI), and hypertension ( P  

  3. Younossi ZM, Ong JP, Takahashi H, Yilmaz Y, Eguchi Y, El Kassas M, et al.
    PMID: 34229038 DOI: 10.1016/j.cgh.2021.06.048
    BACKGROUND & AIMS: Despite rapidly increasing NAFLD prevalence, providers' knowledge may be limited. We assessed NAFLD knowledge and associated factors among physicians of different specialties globally.

    APPROACH & RESULTS: NAFLD knowledge surveys containing 54 and 59 questions covering three domains (Epidemiology/Pathogenesis, Diagnostics, and Treatment) were completed electronically by hepatologists, gastroenterologists (GEs), endocrinologists (ENDOs) and primary care physicians (PCPs) from 40 countries comprising 5 Global Burden of Disease (GBD) super-regions. Over 24 months, 2202 surveys were completed (488 hepatologists, 758 GEs, 148 ENDOs, and 808 PCPs; 50% High-Income GBD super-region, 27% from North Africa and Middle East, 12% Southeast Asia, and 5% South Asian and Latin America). Hepatologists saw the greatest number of NAFLD patients annually: median (IQR) 150 (60-300) vs. 100 (35-200) for GEs, 100 (30-200) for ENDOs, and 10 (4-50) for PCPs (all p<0.0001). The primary sources of NAFLD knowledge acquisition for hepatologists were international conferences (33% vs. 8-26%) and practice guidelines for others (39-44%). Internet was the second most common source of NAFLD knowledge for PCPs (28%). NAFLD knowledge scores were higher for hepatologists than GEs: Epidemiology 62% vs. 53%, Diagnostics 80% vs. 73%, Treatment 61% vs. 58% (p<0.0001) and ENDOs scores were higher than PCPs: Epidemiology 70% vs. 60%, Diagnostics 71% vs. 64%, Treatment 79% vs. 68% (p<0.0001). Being a hepatologist or ENDO was associated with higher knowledge scores than GE or PCP, respectively (p<0.05). Higher NAFLD knowledge scores were independently associated with greater number of NAFLD patients seen (p<0.05).

    CONCLUSION: Despite the growing burden of NAFLD, significant knowledge gap remains for identification, diagnosis and management of NAFLD.

  4. Younossi ZM, Yilmaz Y, Yu ML, Wai-Sun Wong V, Fernandez MC, Isakov VA, et al.
    Clin Gastroenterol Hepatol, 2022 10;20(10):2296-2306.e6.
    PMID: 34768009 DOI: 10.1016/j.cgh.2021.11.004
    BACKGROUND & AIMS: Globally, nonalcoholic fatty liver disease (NAFLD) is a common cause of chronic liver disease. We assessed the clinical presentation and patient-reported outcomes (PROs) among NAFLD patients from different countries.

    METHODS: Clinical, laboratory, and PRO data (Chronic Liver Disease Questionnaire-nonalcoholic steatohepatitis [NASH], Functional Assessment of Chronic Illness Therapy-Fatigue, and the Work Productivity and Activity Index) were collected from NAFLD patients seen in real-world practices and enrolled in the Global NAFLD/NASH Registry encompassing 18 countries in 6 global burden of disease super-regions.

    RESULTS: Across the global burden of disease super-regions, NAFLD patients (n = 5691) were oldest in Latin America and Eastern Europe and youngest in South Asia. Most men were enrolled at the Southeast and South Asia sites. Latin America and South Asia had the highest employment rates (>60%). Rates of cirrhosis varied (12%-21%), and were highest in North Africa/Middle East and Eastern Europe. Rates of metabolic syndrome components varied: 20% to 25% in South Asia and 60% to 80% in Eastern Europe. Chronic Liver Disease Questionnaire-NASH and Functional Assessment of Chronic Illness Therapy-Fatigue PRO scores were lower in NAFLD patients than general population norms (all P < .001). Across the super-regions, the lowest PRO scores were seen in Eastern Europe and North Africa/Middle East. In multivariate analysis adjusted for enrollment region, independent predictors of lower PRO scores included younger age, women, and nonhepatic comorbidities including fatigue (P < .01). Patients whose fatigue scores improved over time experienced a substantial PRO improvement. Nearly 8% of Global NAFLD/NASH Registry patients had a lean body mass index, with fewer metabolic syndrome components, fewer comorbidities, less cirrhosis, and significantly better PRO scores (P < .01).

    CONCLUSIONS: NAFLD patients seen in real-world practices in different countries experience a high comorbidity burden and impaired quality of life. Future research using global data will enable more precise management and treatment strategies for these patients.

  5. Younossi ZM, Yu ML, El-Kassas M, Esmat G, Castellanos Fernández MI, Buti M, et al.
    J Viral Hepat, 2022 Nov;29(11):1015-1025.
    PMID: 36036096 DOI: 10.1111/jvh.13741
    Cure of chronic hepatitis C (CHC) can lead to improvement of health-related quality of life and other patient-reported outcomes (PROs). While extensive PRO data for CHC patients who were enrolled in clinical trials are available, similar data for patients seen in real-world practices are scarce. Our aim was to assess PROs of CHC patients enrolled from real-world practices from different regions and to compare them with those enrolled in clinical trials. CHC patients seen in clinical practices and not receiving treatment were enrolled in the Global Liver Registry (GLR). Clinical and PRO (FACIT-F, CLDQ-HCV, WPAI) data were collected and compared with the baseline data from CHC patients enrolled in clinical trials. N = 12,171 CHC patients were included (GLR n = 3146, clinical trial subjects n = 9025). Patients were from 30 countries from 6 out of 7 Global Burden of Disease (GBD) super-regions. Compared with clinical trial enrollees, patients from GLR were less commonly enrolled from High-Income GBD super-region, older, more commonly female, less employed, had more type 2 diabetes, anxiety and clinically overt fatigue but less cirrhosis (all p  0.05). In conclusion, hepatitis C patients seen in the real-world practices have PRO impairment driven by fatigue and psychiatric comorbidities.
  6. Younossi ZM, Yu ML, Yilmaz Y, Alswat KA, Buti M, Fernandez MIC, et al.
    J Viral Hepat, 2023 Apr;30(4):335-344.
    PMID: 36601668 DOI: 10.1111/jvh.13800
    Chronic hepatitis B (CHB) infection is one of the most common causes of cirrhosis and liver cancer worldwide. Our aim was to assess clinical and patient-reported outcome (PRO) profile of CHB patients from different regions of the world using the Global Liver Registry. The CHB patients seen in real-world practices are being enrolled in the Global Liver Registry. Clinical and PRO (FACIT-F, CLDQ, WPAI) data were collected and compared to baseline data from CHB controls from clinical trials. The study included 1818 HBV subjects (48 ± 13 years, 58% male, 14% advanced fibrosis, 7% cirrhosis) from 15 countries in 6/7 Global Burden of Disease super-regions. The rates of advanced fibrosis varied (3-24%). The lowest PRO scores across multiple domains were in HBV subjects from the Middle East/North Africa (MENA), the highest - Southeast/East and South Asia. Subjects with advanced fibrosis had PRO impairment in 3 CLDQ domains, Activity of WPAI (p  0.10). The clinico-demographic portrait of CHB patients varies across regions of the world and enrollment settings. Advanced fibrosis and non-hepatic comorbidities are independently associated with PRO impairment in CHB patients.
  7. Younossi ZM, Alqahtani SA, Alswat K, Yilmaz Y, Keklikkiran C, Funuyet-Salas J, et al.
    J Hepatol, 2024 Mar;80(3):419-430.
    PMID: 37984709 DOI: 10.1016/j.jhep.2023.11.004
    BACKGROUND & AIMS: Patients with fatty liver disease may experience stigma from the disease or comorbidities. In this cross-sectional study, we aimed to understand stigma among patients with nonalcoholic fatty liver disease (NAFLD)/nonalcoholic steatohepatitis (NASH) and healthcare providers.

    METHODS: Members of the Global NASH Council created two surveys about experiences/attitudes toward NAFLD and related diagnostic terms: a 68-item patient and a 41-item provider survey.

    RESULTS: Surveys were completed by 1,976 patients with NAFLD across 23 countries (51% Middle East/North Africa [MENA], 19% Europe, 17% USA, 8% Southeast Asia, 5% South Asia) and 825 healthcare providers (67% gastroenterologists/hepatologists) across 25 countries (39% MENA, 28% Southeast Asia, 22% USA, 6% South Asia, 3% Europe). Of all patients, 48% ever disclosed having NAFLD/NASH to family/friends; the most commonly used term was "fatty liver" (88% at least sometimes); "metabolic disease" or "MAFLD" were rarely used (never by >84%). Regarding various perceptions of diagnostic terms by patients, there were no substantial differences between "NAFLD", "fatty liver disease (FLD)", "NASH", or "MAFLD". The most popular response was being neither comfortable nor uncomfortable with either term (56%-71%), with slightly greater discomfort with "FLD" among the US and South Asian patients (47-52% uncomfortable). Although 26% of patients reported stigma related to overweight/obesity, only 8% reported a history of stigmatization or discrimination due to NAFLD. Among providers, 38% believed that the term "fatty" was stigmatizing, while 34% believed that "nonalcoholic" was stigmatizing, more commonly in MENA (43%); 42% providers (gastroenterologists/hepatologists 45% vs. 37% other specialties, p = 0.03) believed that the name change to metabolic dysfunction-associated steatotic liver disease (or MASLD) might reduce stigma. Regarding the new nomenclature, the percentage of providers reporting "steatotic liver disease" as stigmatizing was low (14%).

    CONCLUSIONS: The perception of NAFLD stigma varies among patients, providers, geographic locations and sub-specialties.

    IMPACT AND IMPLICATIONS: Over the past decades, efforts have been made to change the nomenclature of nonalcoholic fatty liver disease (NAFLD) to better align with its underlying pathogenetic pathways and remove any potential stigma associated with the name. Given the paucity of data related to stigma in NAFLD, we undertook this global comprehensive survey to assess stigma in NAFLD among patients and providers from around the world. We found there is a disconnect between physicians and patients related to stigma and related nomenclature. With this knowledge, educational programs can be developed to better target stigma in NAFLD among all stakeholders and to provide a better opportunity for the new nomenclature to address the issues of stigma.

  8. Wu XX, Zheng KI, Boursier J, Chan WK, Yilmaz Y, Romero-Gómez M, et al.
    EClinicalMedicine, 2021 Nov;41:101145.
    PMID: 34646997 DOI: 10.1016/j.eclinm.2021.101145
    Background: There is an unmet need for non-invasive biomarkers for the diagnosis of nonalcoholic steatohepatitis (NASH) in non-specialized settings. We aimed to develop and validate a non-invasive test for diagnosing NASH in individuals with biopsy-proven nonalcoholic fatty liver disease (NAFLD).

    Methods: We developed a non-invasive test named the acNASH index that combines serum creatinine and aspartate aminotransferase levels in a derivation cohort of 390 Chinese NAFLD patients admitted to the hepatology center of the First Affiliated Hospital of Wenzhou Medical University (China) between December 2016 and September 2019 and subsequently validated in five external cohorts of different ethnicities of patients with biopsy-confirmed NAFLD (pooled n=1,089).

    Findings: The performance of the acNASH index for identifying NASH (defined as NAFLD activity score ≥5 with score of ≥1 for each steatosis, lobular inflammation and ballooning) was good in the derivation cohort with an area under receiver operating characteristics (AUROC) of 0·818 (95%CI 0·777-0·860). A cutoff of acNASH index <4·15 gave a sensitivity (Se) of 91%, a specificity (Sp) of 48% and a negative predictive value (NPV) of 83% for ruling-out NASH, conversely, a cutoff of acNASH >7·73 gave a Sp of 91%, Se of 53% and a positive predictive value (PPV) of 85% for ruling-in NASH. In the pooled validation cohort (n=1,089), the diagnostic performance of the index was also good with AUROC=0·805 (95%CI 0·780-0·830), NPV of 93% for ruling-out NASH and PPV of 73% for ruling-in NASH. Subgroup analyses showed similar performance in patients with diabetes or subjects with normal serum transaminase levels.

    Interpretation: The acNASH index shows promising utility as a simple non-invasive biomarker for diagnosing NASH among adults with biopsy-proven NAFLD of different ethnicities from different countries.

    Funding: The National Natural Science Foundation of China (82070588), High Level Creative Talents from Department of Public Health in Zhejiang Province (S2032102600032) and Project of New Century 551 Talent Nurturing in Wenzhou.

  9. Sun DQ, Targher G, Byrne CD, Wheeler DC, Wong VW, Fan JG, et al.
    Hepatobiliary Surg Nutr, 2023 Jun 01;12(3):386-403.
    PMID: 37351121 DOI: 10.21037/hbsn-22-421
    BACKGROUND: With the rising global prevalence of fatty liver disease related to metabolic dysfunction, the association of this common liver condition with chronic kidney disease (CKD) has become increasingly evident. In 2020, the more inclusive term metabolic dysfunction-associated fatty liver disease (MAFLD) was proposed to replace the term non-alcoholic fatty liver disease (NAFLD). The observed association between MAFLD and CKD and our understanding that CKD can be a consequence of underlying metabolic dysfunction support the notion that individuals with MAFLD are at higher risk of having and developing CKD compared with those without MAFLD. However, to date, there is no appropriate guidance on CKD in individuals with MAFLD. Furthermore, there has been little attention paid to the link between MAFLD and CKD in the Nephrology community.

    METHODS AND RESULTS: Using a Delphi-based approach, a multidisciplinary panel of 50 international experts from 26 countries reached a consensus on some of the open research questions regarding the link between MAFLD and CKD.

    CONCLUSIONS: This Delphi-based consensus statement provided guidance on the epidemiology, mechanisms, management and treatment of MAFLD and CKD, as well as the relationship between the severity of MAFLD and risk of CKD, which establish a framework for the early prevention and management of these two common and interconnected diseases.

  10. Sirunyan AM, Tumasyan A, Adam W, Asilar E, Bergauer T, Brandstetter J, et al.
    Phys Rev Lett, 2018 Apr 06;120(14):142301.
    PMID: 29694144 DOI: 10.1103/PhysRevLett.120.142301
    The relative yields of ϒ mesons produced in pp and Pb-Pb collisions at sqrt[s_{NN}]=5.02  TeV and reconstructed via the dimuon decay channel are measured using data collected by the CMS experiment. Double ratios are formed by comparing the yields of the excited states, ϒ(2S) and ϒ(3S), to the ground state, ϒ(1S), in both Pb-Pb and pp collisions at the same center-of-mass energy. The double ratios, [ϒ(nS)/ϒ(1S)]_{Pb-Pb}/[ϒ(nS)/ϒ(1S)]_{pp}, are measured to be 0.308±0.055(stat)±0.019(syst) for the ϒ(2S) and less than 0.26 at 95% confidence level for the ϒ(3S). No significant ϒ(3S) signal is found in the Pb-Pb data. The double ratios are studied as a function of collision centrality, as well as ϒ transverse momentum and rapidity. No significant dependencies are observed.
  11. 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^{±}.
  12. 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.
  13. Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Asilar E, Bergauer T, et al.
    Phys Rev Lett, 2018 May 18;120(20):202301.
    PMID: 29864330 DOI: 10.1103/PhysRevLett.120.202301
    The prompt D^{0} meson azimuthal anisotropy coefficients, v_{2} and v_{3}, are measured at midrapidity (|y|<1.0) in Pb-Pb collisions at a center-of-mass energy sqrt[s_{NN}]=5.02  TeV per nucleon pair with data collected by the CMS experiment. The measurement is performed in the transverse momentum (p_{T}) range of 1 to 40  GeV/c, for central and midcentral collisions. The v_{2} coefficient is found to be positive throughout the p_{T} range studied. The first measurement of the prompt D^{0} meson v_{3} coefficient is performed, and values up to 0.07 are observed for p_{T} around 4  GeV/c. Compared to measurements of charged particles, a similar p_{T} dependence, but smaller magnitude for p_{T}<6  GeV/c, is found for prompt D^{0} meson v_{2} and v_{3} coefficients. The results are consistent with the presence of collective motion of charm quarks at low p_{T} and a path length dependence of charm quark energy loss at high p_{T}, thereby providing new constraints on the theoretical description of the interactions between charm quarks and the quark-gluon plasma.
  14. 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.
  15. Sirunyan AM, Tumasyan A, Adam W, Asilar E, Bergauer T, Brandstetter J, et al.
    Phys Rev Lett, 2017 Apr 21;118(16):162301.
    PMID: 28474955 DOI: 10.1103/PhysRevLett.118.162301
    The relative modification of the prompt ψ(2S) and J/ψ yields from pp to PbPb collisions, at the center-of-mass energy of 5.02 TeV per nucleon pair, is presented. The analysis is based on pp and PbPb data samples collected by the CMS experiment at the LHC in 2015, corresponding to integrated luminosities of 28.0  pb^{-1} and 464  μb^{-1}, respectively. The double ratio of measured yields of prompt charmonia reconstructed through their decays into muon pairs, (N_{ψ(2S)}/N_{J/ψ})_{PbPb}/(N_{ψ(2S)}/N_{J/ψ})_{pp}, is determined as a function of PbPb collision centrality and charmonium transverse momentum p_{T}, in two kinematic intervals: |y|<1.6 covering 6.5y|<2.4 covering 3
  16. Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Asilar E, Bergauer T, et al.
    Phys Rev Lett, 2018 Apr 06;120(14):142302.
    PMID: 29694107 DOI: 10.1103/PhysRevLett.120.142302
    Data from heavy ion collisions suggest that the evolution of a parton shower is modified by interactions with the color charges in the dense partonic medium created in these collisions, but it is not known where in the shower evolution the modifications occur. The momentum ratio of the two leading partons, resolved as subjets, provides information about the parton shower evolution. This substructure observable, known as the splitting function, reflects the process of a parton splitting into two other partons and has been measured for jets with transverse momentum between 140 and 500 GeV, in pp and PbPb collisions at a center-of-mass energy of 5.02 TeV per nucleon pair. In central PbPb collisions, the splitting function indicates a more unbalanced momentum ratio, compared to peripheral PbPb and pp collisions.. The measurements are compared to various predictions from event generators and analytical calculations.
  17. 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. 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.
  19. Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Asilar E, Bergauer T, et al.
    Phys Rev Lett, 2019 Jan 18;122(2):021801.
    PMID: 30720313 DOI: 10.1103/PhysRevLett.122.021801
    A search for the Higgs boson decaying to two oppositely charged muons is presented using data recorded by the CMS experiment at the CERN LHC in 2016 at a center-of-mass energy sqrt[s]=13  TeV, corresponding to an integrated luminosity of 35.9  fb^{-1}. Data are found to be compatible with the predicted background. For a Higgs boson with a mass of 125.09 GeV, the 95% confidence level observed (background-only expected) upper limit on the production cross section times the branching fraction to a pair of muons is found to be 3.0 (2.5) times the standard model expectation. In combination with data recorded at center-of-mass energies sqrt[s]=7 and 8 TeV, the background-only expected upper limit improves to 2.2 times the standard model value with a standard model expected significance of 1.0 standard deviation. The corresponding observed upper limit is 2.9 with an observed significance of 0.9 standard deviation. This corresponds to an observed upper limit on the standard model Higgs boson branching fraction to muons of 6.4×10^{-4} and to an observed signal strength of 1.0±1.0(stat)±0.1(syst).
  20. 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.
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links