MyMedR

Piper nigrum Oil - Determination of Selected Terpenes for Quality Evaluation

Wang M, Chittiboyina AG, Parcher JF, Ali Z, Ford P, Zhao J, et al.

Planta Med, 2019 Feb;85(3):185-194.

The growing demand and commercial value of black pepper (Piper nigrum) has resulted in considerable interest in developing suitable and cost-effective methods for chemical characterization and quality evaluation purposes. In the current study, an extensive set of oil samples (n = 23) that were extracted by steam distillation from black pepper seeds was investigated to compare the chemical profiles of samples originating from nine major producing countries, as well as to identify potential chemical markers for quality evaluation. The twenty-two most abundant volatile compounds, mainly terpenes, in these oils were determined by conventional GC/MS analysis. Principal component analysis with this set of data revealed distinct clusters for samples that originated from China and Malaysia. Relatively low concentrations of sabinene (

Assessing urban flooding risk in response to climate change and urbanization based on shared socio-economic pathways

Wang M, Fu X, Zhang D, Chen F, Liu M, Zhou S, et al.

Sci Total Environ, 2023 Jul 01;880:163470.

PMID: 37076008 DOI: 10.1016/j.scitotenv.2023.163470

Global climate change and rapid urbanization, mainly driven by anthropogenic activities, lead to urban flood vulnerability and uncertainty in sustainable stormwater management. This study projected the temporal and spatial variation in urban flood susceptibility during the period 2020-2050 on the basis of shared socioeconomic pathways (SSPs). A case study in Guangdong-Hong Kong-Macao Greater Bay Area (GBA) was conducted for verifying the feasibility and applicability of this approach. GBA is predicted to encounter the increase in extreme precipitation with high intensity and frequency, along with rapid expansion of constructed areas, resulting in exacerbating of urban flood susceptibility. The areas with medium and high flood susceptibility will be expected to increase continuously from 2020 to 2050, by 9.5 %, 12.0 %, and 14.4 % under SSP1-2.6, SSP2-4.5, and SSP5-8.5 scenarios, respectively. In terms of the assessment of spatial-temporal flooding pattern, the areas with high flood susceptibility are overlapped with that in the populated urban center in GBA, surrounding the existing risk areas, which is consistent with the tendency of construction land expansion. The approach in the present study will provide comprehensive insights into the reliable and accurate assessment of urban flooding susceptibility in response to climate change and urbanization.

Unveiling the Microfiber Release Footprint: Guiding Control Strategies in the Textile Production Industry

Wang M, Yang J, Zheng S, Jia L, Yong ZY, Yong EL, et al.

Environ Sci Technol, 2023 Dec 19;57(50):21038-21049.

PMID: 38064758 DOI: 10.1021/acs.est.3c06210

Microplastic fibers from textiles have been known to significantly contribute to marine microplastic pollution. However, little is known about the microfiber formation and discharge during textile production. In this study, we have quantified microfiber emissions from one large and representative textile factory during different stages, spanning seven different materials, including cotton, polyester, and blended fabrics, to further guide control strategies. Wet-processing steps released up to 25 times more microfibers than home laundering, with dyeing contributing to 95.0% of the total emissions. Microfiber release could be reduced by using white coloring, a lower dyeing temperature, and a shorter dyeing duration. Thinner, denser yarns increased microfiber pollution, whereas using tightly twisted fibers mitigated release. Globally, wet textile processing potentially produced 6.4 kt of microfibers in 2020, with China, India, and the US as significant contributors. The study underlined the environmental impact of textile production and the need for mitigation strategies, particularly in dyeing processes and fiber choice. In addition, no significant difference was observed between the virgin polyesters and the used ones. Replacing virgin fibers with recycled fibers in polyester fabrics, due to their increasing consumption, might offer another potential solution. The findings highlighted the substantial impact of textile production on microfiber released into the environment, and optimization of material selection, knitting technologies, production processing, and recycled materials could be effective mitigation strategies.

Baseline retinal nerve fiber layer thickness as a predictor of multiple sclerosis progression: New insights from the FREEDOMS II study

Wang L, Tan H, Yu J, ZhangBao J, Huang W, Chang X, et al.

Eur J Neurol, 2023 Feb;30(2):443-452.

PMID: 36286605 DOI: 10.1111/ene.15612

BACKGROUND AND PURPOSE: The aim was to evaluate the potential of retinal nerve fiber layer thickness (RNFLT) measured with optical coherence tomography in predicting disease progression in relapsing-remitting multiple sclerosis (RRMS).

METHODS: Analyses were conducted post hoc of this 24-month, phase III, double-blind study, in which RRMS patients were randomized (1:1:1) to once daily oral fingolimod 0.5 mg, 1.25 mg or placebo. The key outcomes were the association between baseline RNFLT and baseline clinical characteristics and clinical/imaging outcomes up to 24 months. Change of RNFLT with fingolimod versus placebo within 24 months and time to retinal nerve fiber layer (RNFL) thinning were evaluated.

RESULTS: Altogether 885 patients were included. At baseline, lower RNFLT was correlated with higher Expanded Disability Status Scale score (r = -1.085, p = 0.018), lower brain volume (r = 0.025, p = 0.006) and deep gray matter volume (r = 0.731, p

Fulltext Psychrobacter Phage Encoding an Antibiotics Resistance Gene Represents a Novel Caudoviral Family

Wang H, Ren L, Liang Y, Zheng K, Guo R, Liu Y, et al.

Microbiol Spectr, 2023 Aug 17;11(4):e0533522.

PMID: 37272818 DOI: 10.1128/spectrum.05335-22

Psychrobacter is an important bacterial genus that is widespread in Antarctic and marine environments. However, to date, only two complete Psychrobacter phage sequences have been deposited in the NCBI database. Here, the novel Psychrobacter phage vB_PmaS_Y8A, infecting Psychrobacter HM08A, was isolated from sewage in the Qingdao area, China. The morphology of vB_PmaS_Y8A was characterized by transmission electron microscopy, revealing an icosahedral head and long tail. The genomic sequence of vB_PmaS_Y8A is linear, double-stranded DNA with a length of 40,226 bp and 44.1% G+C content, and encodes 69 putative open reading frames. Two auxiliary metabolic genes (AMGs) were identified, encoding phosphoadenosine phosphosulfate reductase and MarR protein. The first AMG uses thioredoxin as an electron donor for the reduction of phosphoadenosine phosphosulfate to phosphoadenosine phosphate. MarR regulates multiple antibiotic resistance mechanisms in Escherichia coli and is rarely found in viruses. No tRNA genes were identified and no lysogeny-related feature genes were detected. However, many similar open reading frames (ORFs) were found in the host genome, which may indicate that Y8A also has a lysogenic stage. Phylogenetic analysis based on the amino acid sequences of whole genomes and comparative genomic analysis indicate that vB_PmaS_Y8A contains a novel genomic architecture similar only to that of Psychrobacter phage pOW20-A, although at a low similarity. vB_PmaS_Y8A represents a new family-level virus cluster with 22 metagenomic assembled viral genomes, here named Minviridae. IMPORTANCE Although Psychrobacter is a well-known and important bacterial genus that is widespread in Antarctic and marine environments, genetic characterization of its phages is still rare. This study describes a novel Psychrobacter phage containing an uncharacterized antibiotic resistance gene and representing a new virus family, Minviridae. The characterization provided here will bolster current understanding of genomes, diversity, evolution, and phage-host interactions in Psychrobacter populations.

Fulltext Shewanella phage encoding a putative anti-CRISPR-like gene represents a novel potential viral family

Wang H, Zheng K, Wang M, Ma K, Ren L, Guo R, et al.

Microbiol Spectr, 2024 Feb 06;12(2):e0336723.

PMID: 38214523 DOI: 10.1128/spectrum.03367-23

Shewanella is a prevalent bacterial genus in deep-sea environments including marine sediments, exhibiting diverse metabolic capabilities that indicate its significant contributions to the marine biogeochemical cycles. However, only a few Shewanella phages were isolated and deposited in the NCBI database. In this study, we report the isolation and characterization of a novel Shewanella phage, vB_SbaS_Y11, that infects Shewanella KR11 and was isolated from the sewage in Qingdao, China. Transmission electron microscopy revealed that vB_SbaS_Y11 has an icosahedral head and a long tail. The genome of vB_SbaS_Y11 is a linear, double-stranded DNA with a length of 62,799 bp and a G+C content of 46.9%, encoding 71 putative open reading frames. No tRNA genes or integrase-related feature genes were identified. An uncharacterized anti-CRISPR AcrVA2 gene was detected in its genome. Phylogenetic analysis based on the amino acid sequences of whole genomes and comparative genomic analyses indicate that vB_SbaS_Y11 has a novel genomic architecture and shares low similarity to Pseudomonas virus H66 and Pseudomonas phage F116. vB_SbaS_Y11 represents a potential new family-level virus cluster with eight metagenomic assembled viral genomes named Ranviridae.IMPORTANCEThe Gram-negative Shewanella bacterial genus currently includes about 80 species of mostly aquatic Gammaproteobacteria, which were isolated around the globe in a multitude of environments, such as freshwater, seawater, coastal sediments, and the deepest trenches. Here, we present a Shewanella phage vB_SbaS_Y11 that contains an uncharacterized anti-CRISPR AcrVA2 gene and belongs to a potential virus family, Ranviridae. This study will enhance the knowledge about the genome, diversity, taxonomic classification, and global distribution of Shewanella phage populations.

Fractionation of oil palm empty fruit bunch by bisulfite pretreatment for the production of bioethanol and high value products

Tan L, Wang M, Li X, Li H, Zhao J, Qu Y, et al.

Bioresour Technol, 2016 Jan;200:572-8.

PMID: 26539970 DOI: 10.1016/j.biortech.2015.10.079

In this work, fractionation of empty fruit bunch (EFB) by bisulfite pretreatment was studied for the production of bioethanol and high value products to achieve biorefinery of EFB. EFB was fractionated to solid and liquor components by bisulfite process. The solid components were used for bioethanol production by quasi-simultaneous saccharification and fermentation. The liquor components were then converted to furfural by hydrolysis with sulfuric acid. Preliminary results showed that the concentration of furfural was highest at 18.8g/L with 0.75% sulfuric acid and reaction time of 25min. The conversion of xylose to furfural was 82.5%. Furthermore, we attempted to fractionate the liquor into hemicellulose sugars and lignin by different methods for producing potential chemicals, such as xylose, xylooligosaccharide, and lignosulfonate. Our research showed that the combination of bisulfite pretreatment and resin separation could effectively fractionate EFB components to produce bioethanol and other high value chemicals.

Inguinal Hernia: Mesh Fixation

Sun P, Hu SB, Cheng X, Li M, Guo B, Song ZF, et al.

Hernia, 2015 Apr;19 Suppl 1:S157-65.

PMID: 26518794 DOI: 10.1007/BF03355344

Fulltext Identification and genomic analysis of temperate Halomonas bacteriophage vB_HmeY_H4907 from the surface sediment of the Mariana Trench at a depth of 8,900 m

Su Y, Zhang W, Liang Y, Wang H, Liu Y, Zheng K, et al.

Microbiol Spectr, 2023 Sep 20;11(5):e0191223.

PMID: 37728551 DOI: 10.1128/spectrum.01912-23

Viruses play crucial roles in the ecosystem by modulating the host community structure, mediating biogeochemical cycles, and compensating for the metabolism of host cells. Mariana Trench, the world's deepest hadal habitat, harbors a variety of unique microorganisms that have adapted to its extreme conditions of low temperatures, high pressure, and nutrient scarcity. However, our knowledge about isolated hadal phage strains in the hadal trench is still limited. This study reported the discovery of a temperate phage, vB_HmeY_H4907, infecting Halomonas meridiana H4907, isolated from surface sediment from the Mariana Trench at a depth of 8,900 m. To our best knowledge, it is the deepest isolated siphovirus from the ocean. Its 40,452 bp linear dsDNA genome has 57.64% GC content and 55 open reading frames, and it is highly homologous to its host. Phylogenetic analysis and average nucleotide sequence identification reveal that vB_HmeY_H4907 is separated from the isolated phages and represents a new family, Suviridae, with eight predicted proviruses and six uncultured viral genomes. They are widely distributed in the ocean, suggesting a prevalence of this viral family in the deep sea. These findings expand our understanding of the phylogenetic diversity and genomic features of hadal lysogenic phages, provide essential information for further studies of phage-host interactions and evolution, and may reveal new insights into the lysogenic lifestyles of viruses inhabiting the hadal ocean. IMPORTANCE Halomonas phage vB_HmeY_H4907 is the deepest isolated siphovirus from the ocean, and it represents a novel abundant viral family in the ocean. This study provides insights into the genomic, phylogenetic, and ecological characteristics of the new viral family, namely, Suviridae.

The association between psychological strain and suicidal behaviors among college students: A mental health survey in Jilin Province, Northeast China

Song Y, Bai W, Wang M, Liu X, Zhang L, Yu W, et al.

J Affect Disord, 2019 12 01;259:195-200.

PMID: 31446380 DOI: 10.1016/j.jad.2019.08.042

BACKGROUND: Suicide is a major global mental health problem among college students. The aim of the current study was to explore the association between the psychological strains of the strain theory of suicide and suicidal behaviors among college students.

METHODS: Participants comprised 1912 college students (16-28 years old, 47.2% female) from three universities in Jilin Province, China, who completed the self-report assessments of psychological strains (40 items Psychological Strains Scale) and suicidal behaviors (Suicidal Behaviors Questionnaire-Revised). The demographic characteristics included four variables: health status, psychological status, academic status and economic status.

RESULTS: Approximately 15.0% (286/1912) of participants were classified as having suicide risk, based on the cut-off scores of the SBQ-R. The prevalence of suicidal behaviors among males and females was 11.9% (120/1009) and 18.4% (166/903), respectively. Value strain (OR = 1.075, 95%CI: 1.057-1.094), aspiration strain (OR = 1.082, 95%CI: 1.064-1.101), deprivation strain (OR = 1.073, 95%CI: 1.052-1.093), and coping strain (OR = 1.095, 95%CI: 1.075-1.116) were risk factors for suicidality in college students. Coping strain (OR = 1.050, 95%CI: 1.023-1.077) was still positively associated with suicide risk in multivariate logistic regression. Logistic regression analysis indicated that coping strain had the highest correlation with suicidal behaviors.

LIMITATIONS: The directionality of the relationships cannot be deduced because this study is cross-sectional.

CONCLUSION: This study confirms a strong association between psychological strains and suicidal behaviors in college students. Some measures can be taken to reduce psychological strains to mitigate suicide risk among college students. More studies investigating coping strain among college students are warranted.

Fulltext Suppression of Excited ϒ States Relative to the Ground State in Pb-Pb Collisions at sqrt[s]_{NN}=5.02 TeV

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.

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

Observation of the B_{s}^{0}→X(3872)ϕ Decay

Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Bergauer T, Dragicevic M, et al.

Phys Rev Lett, 2020 Oct 09;125(15):152001.

PMID: 33095627 DOI: 10.1103/PhysRevLett.125.152001

Using a data sample of proton-proton collisions at sqrt[s]=13 TeV, corresponding to an integrated luminosity of 140 fb^{-1} collected by the CMS experiment in 2016-2018, the B_{s}^{0}→X(3872)ϕ decay is observed. Decays into J/ψπ^{+}π^{-} and K^{+}K^{-} are used to reconstruct, respectively, the X(3872) and ϕ. The ratio of the product of branching fractions B[B_{s}^{0}→X(3872)ϕ]B[X(3872)→J/ψπ^{+}π^{-}] to the product B[B_{s}^{0}→ψ(2S)ϕ]B[ψ(2S)→J/ψπ^{+}π^{-}] is measured to be [2.21±0.29(stat)±0.17(syst)]%. The ratio B[B_{s}^{0}→X(3872)ϕ]/B[B^{0}→X(3872)K^{0}] is found to be consistent with one, while the ratio B[B_{s}^{0}→X(3872)ϕ]/B[B^{+}→X(3872)K^{+}] is two times smaller. This suggests a difference in the production dynamics of the X(3872) in B^{0} and B_{s}^{0} meson decays compared to B^{+}. The reported observation may shed new light on the nature of the X(3872) particle.

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^{±}.

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.

Measurement of Prompt D^{0} Meson Azimuthal Anisotropy 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, 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.

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.

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.

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.

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.

Displaying publications 21 - 40 of 196 in total