Showing papers by "Istanbul Technical University published in 2015"
TL;DR: A measurement of the Higgs boson mass is presented based on the combined data samples of the ATLAS and CMS experiments at the CERN LHC in the H→γγ and H→ZZ→4ℓ decay channels.
Abstract: A measurement of the Higgs boson mass is presented based on the combined data samples of the ATLAS and CMS experiments at the CERN LHC in the H→γγ and H→ZZ→4l decay channels. The results are obtained from a simultaneous fit to the reconstructed invariant mass peaks in the two channels and for the two experiments. The measured masses from the individual channels and the two experiments are found to be consistent among themselves. The combined measured mass of the Higgs boson is mH=125.09±0.21 (stat)±0.11 (syst) GeV.
1,567 citations
Vardan Khachatryan1, Albert M. Sirunyan1, Armen Tumasyan1, Wolfgang Adam +2134 more•Institutions (142)
TL;DR: The couplings of the Higgs boson are probed for deviations in magnitude from the standard model predictions in multiple ways, including searches for invisible and undetected decays, and no significant deviations are found.
Abstract: Properties of the Higgs boson with mass near 125 GeV are measured in proton-proton collisions with the CMS experiment at the LHC. Comprehensive sets of production and decay measurements are combined. The decay channels include gamma gamma, ZZ, WW, tau tau, bb, and mu mu pairs. The data samples were collected in 2011 and 2012 and correspond to integrated luminosities of up to 5.1 inverse femtobarns at 7 TeV and up to 19.7 inverse femtobarns at 8 TeV. From the high-resolution gamma gamma and ZZ channels, the mass of the Higgs boson is determined to be 125.02 +0.26 -0.27 (stat) +0.14 -0.15 (syst) GeV. For this mass value, the event yields obtained in the different analyses tagging specific decay channels and production mechanisms are consistent with those expected for the standard model Higgs boson. The combined best-fit signal relative to the standard model expectation is 1.00 +/- 0.09 (stat) +0.08 -0.07 (theo) +/- 0.07 (syst) at the measured mass. The couplings of the Higgs boson are probed for deviations in magnitude from the standard model predictions in multiple ways, including searches for invisible and undetected decays. No significant deviations are found.
677 citations
Vardan Khachatryan1, Albert M. Sirunyan1, Armen Tumasyan1, Wolfgang Adam2 +2802 more•Institutions (215)
TL;DR: In this paper, the branching fractions of the B meson (B-s(0)) and the B-0 meson decaying into two oppositely charged muons (mu(+) and mu(-)) were observed.
Abstract: The standard model of particle physics describes the fundamental particles and their interactions via the strong, electromagnetic and weak forces. It provides precise predictions for measurable quantities that can be tested experimentally. The probabilities, or branching fractions, of the strange B meson (B-s(0)) and the B-0 meson decaying into two oppositely charged muons (mu(+) and mu(-)) are especially interesting because of their sensitivity to theories that extend the standard model. The standard model predicts that the B-s(0)->mu(+)mu(-) and B-0 ->mu(+)mu(-) decays are very rare, with about four of the former occurring for every billion B-s(0) mesons produced, and one of the latter occurring for every ten billion B-0 mesons(1). A difference in the observed branching fractions with respect to the predictions of the standard model would provide a direction in which the standard model should be extended. Before the Large Hadron Collider (LHC) at CERN2 started operating, no evidence for either decay mode had been found. Upper limits on the branching fractions were an order of magnitude above the standard model predictions. The CMS (Compact Muon Solenoid) and LHCb(Large Hadron Collider beauty) collaborations have performed a joint analysis of the data from proton-proton collisions that they collected in 2011 at a centre-of-mass energy of seven teraelectronvolts and in 2012 at eight teraelectronvolts. Here we report the first observation of the B-s(0)->mu(+)mu(-) decay, with a statistical significance exceeding six standard deviations, and the best measurement so far of its branching fraction. Furthermore, we obtained evidence for the B-0 ->mu(+)mu(-) decay with a statistical significance of three standard deviations. Both measurements are statistically compatible with standard model predictions and allow stringent constraints to be placed on theories beyond the standard model. The LHC experiments will resume taking data in 2015, recording proton-proton collisions at a centre-of-mass energy of 13 teraelectronvolts, which will approximately double the production rates of B-s(0) and B-0 mesons and lead to further improvements in the precision of these crucial tests of the standard model.
467 citations
441 citations
Vardan Khachatryan1, Albert M. Sirunyan1, Armen Tumasyan1, Wolfgang Adam2 +2119 more•Institutions (141)
TL;DR: In this paper, a search for particle dark matter (DM), extra dimensions, and unparticles using events containing a jet and an imbalance in transverse momentum was conducted at the LHC.
Abstract: Results are presented from a search for particle dark matter (DM), extra dimensions, and unparticles using events containing a jet and an imbalance in transverse momentum. The data were collected by the CMS detector in proton-proton collisions at the LHC and correspond to an integrated luminosity of 19.7 fb$^{-1}$ at a centre-of-mass energy of 8 TeV. The number of observed events is found to be consistent with the standard model prediction. Limits are placed on the DM-nucleon scattering cross section as a function of the DM particle mass for spin-dependent and spin-independent interactions. Limits are also placed on the scale parameter $M_\mathrm{D}$ in the ADD model of large extra dimensions, and on the unparticle model parameter $\Lambda_\mathrm{U}$. The constraints on ADD models and unparticles are the most stringent limits in this channel and those on the DM-nucleon scattering cross section are an improvement over previous collider results.
425 citations
Vardan Khachatryan, Albert M. Sirunyan, Armen Tumasyan, Wolfgang Adam1 +2114 more•Institutions (146)
TL;DR: In this article, the spin-parity and tensor structure of the interactions of the recently discovered Higgs boson is performed using the H to ZZ, Z gamma*, gamma* gamma* to 4 l, H to WW to l nu l nu, and H to gamma gamma decay modes.
Abstract: The study of the spin-parity and tensor structure of the interactions of the recently discovered Higgs boson is performed using the H to ZZ, Z gamma*, gamma* gamma* to 4 l, H to WW to l nu l nu, and H to gamma gamma decay modes. The full dataset recorded by the CMS experiment during the LHC Run 1 is used, corresponding to an integrated luminosity of up to 5.1 inverse femtobarns at a center-of-mass energy of 7 TeV and up to 19.7 inverse femtobarns at 8 TeV. A wide range of spin-two models is excluded at a 99% confidence level or higher, or at a 99.87% confidence level for the minimal gravity-like couplings, regardless of whether assumptions are made on the production mechanism. Any mixed-parity spin-one state is excluded in the ZZ and WW modes at a greater than 99.999% confidence level. Under the hypothesis that the resonance is a spin-zero boson, the tensor structure of the interactions of the Higgs boson with two vector bosons ZZ, Z gamma, gamma gamma, and WW is investigated and limits on eleven anomalous contributions are set. Tighter constraints on anomalous HVV interactions are obtained by combining the HZZ and HWW measurements. All observations are consistent with the expectations for the standard model Higgs boson with the quantum numbers J[PC]=0[++].
399 citations
University of Toronto1, Enel2, Beijing Normal University3, TERI University4, De La Salle University5, Seoul National University6, Federal University of Rio de Janeiro7, University of California, Los Angeles8, Imperial College London9, University of Paris10, Trisakti University11, University of Lagos12, University of Tehran13, Bangladesh University of Engineering and Technology14, Hunter College15, United States Environmental Protection Agency16, NED University of Engineering and Technology17, Universidad de Guanajuato18, Istanbul Technical University19
TL;DR: The quantification of energy and material flows for the world’s 27 megacities with populations greater than 10 million people as of 2010 is a major undertaking, not previously achieved and largely consistent with scaling laws established in the emerging science of cities.
Abstract: Understanding the drivers of energy and material flows of cities is important for addressing global environmental challenges. Accessing, sharing, and managing energy and material resources is particularly critical for megacities, which face enormous social stresses because of their sheer size and complexity. Here we quantify the energy and material flows through the world’s 27 megacities with populations greater than 10 million people as of 2010. Collectively the resource flows through megacities are largely consistent with scaling laws established in the emerging science of cities. Correlations are established for electricity consumption, heating and industrial fuel use, ground transportation energy use, water consumption, waste generation, and steel production in terms of heating-degree-days, urban form, economic activity, and population growth. The results help identify megacities exhibiting high and low levels of consumption and those making efficient use of resources. The correlation between per capita electricity use and urbanized area per capita is shown to be a consequence of gross building floor area per capita, which is found to increase for lower-density cities. Many of the megacities are growing rapidly in population but are growing even faster in terms of gross domestic product (GDP) and energy use. In the decade from 2001–2011, electricity use and ground transportation fuel use in megacities grew at approximately half the rate of GDP growth.
383 citations
TL;DR: This paper surveys the latest status of fuzzy multicriteria decision-making methods and classify these methods dividing into two parts: fuzzy multiattribute decision- Making (MADM) and fuzzy multiobjective decision- making (MODM).
Abstract: Multicriteria decision-making (MCDM) refers to making decisions in the presence of multiple and usually conflicting criteria. Fuzzy decision-making is used where vague and incomplete data exist for the solution. Fuzzy multicriteria decision-making is one of the most popular problems handled by the researchers in the literature. In this paper, we survey the latest status of fuzzy multicriteria decision-making methods and classify these methods dividing into two parts: fuzzy multiattribute decision-making (MADM) and fuzzy multiobjective decision-making (MODM). Most of the publications are on fuzzy MADM since there are a plenty of classical multiattribute decision-making methods in the literature. Tabular and graphical illustrations for each method are given.
376 citations
Vardan Khachatryan1, Robin Erbacher2, C. A. Carrillo Montoya3, Chang-Seong Moon +2154 more•Institutions (149)
TL;DR: The first direct search for lepton-flavour-violating decays of the recently discovered Higgs boson (H) is described in this paper, where the search is performed in the H→μτ_e and H→mτ_h channels, where τeτe and τ_h are tau leptons reconstructed in the electronic and hadronic decay channels, respectively.
285 citations
Vardan Khachatryan, Albert M. Sirunyan, Armen Tumasyan, Wolfgang Adam1 +2204 more•Institutions (181)
TL;DR: In this paper, the performance of the Cern LHC detector for photon reconstruction and identification in proton-proton collisions at a centre-of-mass energy of 8 TeV at the CERN LHC is described.
Abstract: A description is provided of the performance of the CMS detector for photon reconstruction and identification in proton-proton collisions at a centre-of-mass energy of 8 TeV at the CERN LHC. Details are given on the reconstruction of photons from energy deposits in the electromagnetic calorimeter (ECAL) and the extraction of photon energy estimates. The reconstruction of electron tracks from photons that convert to electrons in the CMS tracker is also described, as is the optimization of the photon energy reconstruction and its accurate modelling in simulation, in the analysis of the Higgs boson decay into two photons. In the barrel section of the ECAL, an energy resolution of about 1% is achieved for unconverted or late-converting photons from H→γγ decays. Different photon identification methods are discussed and their corresponding selection efficiencies in data are compared with those found in simulated events.
272 citations
TL;DR: The results indicate that the proposed Vortex Search algorithm outperforms the SA, PS and ABC algorithms while being competitive with the PSO2011 algorithm.
Vardan Khachatryan, Albert M. Sirunyan, Armen Tumasyan, Wolfgang Adam1 +2127 more•Institutions (146)
TL;DR: In this article, a search for resonances and quantum black holes is performed using the dijet mass spectra measured in proton-proton collisions at s√=8 TeV with the CMS detector at the LHC.
Abstract: A search for resonances and quantum black holes is performed using the dijet mass spectra measured in proton-proton collisions at s√=8 TeV with the CMS detector at the LHC. The data set corresponds to an integrated luminosity of 19.7 fb^(−1). In a search for narrow resonances that couple to quark-quark, quark-gluon, or gluon-gluon pairs, model-independent upper limits, at 95% confidence level, are obtained on the production cross section of resonances, with masses above 1.2 TeV. When interpreted in the context of specific models the limits exclude string resonances with masses below 5.0 TeV; excited quarks below 3.5 TeV; scalar diquarks below 4.7 TeV; W′ bosons below 1.9 TeV or between 2.0 and 2.2 TeV; Z′ bosons below 1.7 TeV; and Randall-Sundrum gravitons below 1.6 TeV. A separate search is conducted for narrow resonances that decay to final states including b quarks. The first exclusion limit is set for excited b quarks, with a lower mass limit between 1.2 and 1.6 TeV depending on their decay properties. Searches are also carried out for wide resonances, assuming for the first time width-to-mass ratios up to 30%, and for quantum black holes with a range of model parameters. The wide resonance search excludes axigluons and colorons with mass below 3.6 TeV, and color-octet scalars with mass below 2.5 TeV. Lower bounds between 5.0 and 6.3 TeV are set on the masses of quantum black holes.
Queen Mary University of London1, Vita-Salute San Raffaele University2, Erasmus University Rotterdam3, University of Montpellier4, University of Bari5, Karolinska Institutet6, Autonomous University of Barcelona7, VU University Amsterdam8, Innsbruck Medical University9, Charles University in Prague10, University of Ulm11, University of Barcelona12, Istanbul Technical University13, Istanbul University14, University of Düsseldorf15, University of Szeged16, Aix-Marseille University17, University of Graz18, Claude Bernard University Lyon 119, University of Copenhagen20, University of Gothenburg21, University of Milan22, University of Bergen23, University of Genoa24, Medical University of Lublin25, University of Toulouse26, University Hospital of Basel27, University of Oxford28
TL;DR: MRI lesion load, OCB and age at CIS are validated as the strongest independent predictors of conversion to CDMS in this multicentre setting.
Abstract: We explored which clinical and biochemical variables predict conversion from clinically isolated syndrome (CIS) to clinically definite multiple sclerosis (CDMS) in a large international cohort. Thirty-three centres provided serum samples from 1047 CIS cases with at least two years' follow-up. Age, sex, clinical presentation, T2-hyperintense lesions, cerebrospinal fluid (CSF) oligoclonal bands (OCBs), CSF IgG index, CSF cell count, serum 25-hydroxyvitamin D3 (25-OH-D), cotinine and IgG titres against Epstein-Barr nuclear antigen 1 (EBNA-1) and cytomegalovirus were tested for association with risk of CDMS. At median follow-up of 4.31 years, 623 CIS cases converted to CDMS. Predictors of conversion in multivariable analyses were OCB (HR = 2.18, 95% CI = 1.71-2.77, p 9 lesions vs 0/1 lesions: HR = 2.74, 95% CI = 2.04-3.68, p < 0.001) and age at CIS (HR per year inversely increase = 0.98, 95% CI = 0.98-0.99, p < 0.001). Lower 25-OH-D levels were associated with CDMS in univariable analysis, but this was attenuated in the multivariable model. OCB positivity was associated with higher EBNA-1 IgG titres. We validated MRI lesion load, OCB and age at CIS as the strongest independent predictors of conversion to CDMS in this multicentre setting. A role for vitamin D is suggested but requires further investigation.
16 May 2015
TL;DR: Comparison of students and professionals in software engineering to understand how well students represent professionals as experimental subjects in SE research finds similar performances.
Abstract: -- Background: Most of the experiments in software engineering (SE) employ students as subjects. This raises concerns about the realism of the results acquired through students and adaptability of the results to software industry. Aim: We compare students and professionals to understand how well students represent professionals as experimental subjects in SE research. Method: The comparison was made in the context of two test-driven development experiments conducted with students in an academic setting and with professionals in a software organization. We measured the code quality of several tasks implemented by both subject groups and checked whether students and professionals perform similarly in terms of code quality metrics. Results: Except for minor differences, neither of the subject groups is better than the other. Professionals produce larger, yet less complex, methods when they use their traditional development approach, whereas both subject groups perform similarly when they apply a new approach for the first time. Conclusion: Given a carefully scoped experiment on a development approach that is new to both students and professionals, similar performances are observed. Further investigation is necessary to analyze the effects of subject demographics and level of experience on the results of SE experiments.
Vardan Khachatryan, Albert M. Sirunyan, Armen Tumasyan, Wolfgang Adam1 +2137 more•Institutions (148)
TL;DR: The second-order azimuthal anisotropy Fourier Fourier harmonics, v2, obtained in p-Pb and PbPb collisions over a wide pseudorapidity range based on correlations among six or more charged particles support the interpretation of a collective origin for the previously observed long-range (large Δη) correlations in both systems.
Abstract: The second-order azimuthal anisotropy Fourier harmonics, v2, are obtained in pPb and PbPb collisions over a wide pseudorapidity (eta) range based on correlations among six or more charged particles. The pPb data, corresponding to an integrated luminosity of 35 inverse nanobarns, were collected during the 2013 LHC pPb run at a nucleon-nucleon center-of-mass energy of 5.02 TeV by the CMS experiment. A sample of semi-peripheral PbPb collision data at sqrt(s[NN])= 2.76 TeV, corresponding to an integrated luminosity of 2.5 inverse microbarns and covering a similar range of particle multiplicities as the pPb data, is also analyzed for comparison. The six- and eight-particle cumulant and the Lee-Yang zeros methods are used to extract the v2 coefficients, extending previous studies of two- and four-particle correlations. For both the pPb and PbPb systems, the v2 values obtained with correlations among more than four particles are consistent with previously published four-particle results. These data support the interpretation of a collective origin for the previously observed long-range (large Delta[eta]) correlations in both systems. The ratios of v2 values corresponding to correlations including different numbers of particles are compared to theoretical predictions that assume a hydrodynamic behavior of a pPb system dominated by fluctuations in the positions of participant nucleons. These results provide new insights into the multi-particle dynamics of collision systems with a very small overlapping region.
Vardan Khachatryan1, Albert M. Sirunyan1, Armen Tumasyan1, Wolfgang Adam +2353 more•Institutions (181)
TL;DR: In this paper, a search for a heavy Higgs boson in the H to WW and H to ZZ decay channels is reported, based upon proton-proton collision data samples corresponding to an integrated luminosity of up to 5.1 inverse femtobarns at sqrt(s)=7 TeV and up to 19.7 inverse femto-bars at square root of 8 TeV, recorded by the CMS experiment at the CERN LHC.
Abstract: A search for a heavy Higgs boson in the H to WW and H to ZZ decay channels is reported. The search is based upon proton-proton collision data samples corresponding to an integrated luminosity of up to 5.1 inverse femtobarns at sqrt(s)=7 TeV and up to 19.7 inverse femtobarns at sqrt(s)=8 TeV, recorded by the CMS experiment at the CERN LHC. Several final states of the H to WW and H to ZZ decays are analyzed. The combined upper limit at the 95% confidence level on the product of the cross section and branching fraction exclude a Higgs boson with standard model-like couplings and decays in the range 145 < m[H] < 1000 GeV. We also interpret the results in the context of an electroweak singlet extension of the standard model.
Vardan Khachatryan1, Albert M. Sirunyan1, Armen Tumasyan1, Wolfgang Adam +2122 more•Institutions (140)
TL;DR: In this article, the normalized differential cross section for top quark pair (tt) production is measured in pp collisions at a centre-of-mass energy of 8TeV at the CERN LHC using the CMS detector in data corresponding to an integrated luminosity of 19.7fb^(−1).
Abstract: The normalized differential cross section for top quark pair (tt) production is measured in pp collisions at a centre-of-mass energy of 8TeV at the CERN LHC using the CMS detector in data corresponding to an integrated luminosity of 19.7fb^(−1). The measurements are performed in the lepton+jets (e/μ +jets) and in the dilepton (e^+e^−, μ^+μ^−, and e^±μ^∓) decay channels. The tt cross section is measured as a function of the kinematic properties of the charged leptons, the jets associated to b quarks, the top quarks, and the tt system. The data are compared with several predictions from perturbative quantum chromodynamic up to approximate next-to-next-to-leading-order precision. No significant deviations are observed relative to the standard model predictions.
TL;DR: In this article, the authors discuss the evolution of anaerobic sludge bed technology for the treatment of industrial wastewaters in the last four decades, focusing on granular SLB systems.
Abstract: In the last 40 years, anaerobic sludge bed reactor technology evolved from localized lab-scale trials to worldwide successful implementations at a variety of industries. High-rate sludge bed reactors are characterized by a very small foot print and high applicable volumetric loading rates. Best performances are obtained when the sludge bed consists of highly active and well settleable granular sludge. Sludge granulation provides a rich microbial diversity, high biomass concentration, high solids retention time, good settling characteristics, reduction in both the operation costs and reactor volume, and high tolerance to inhibitors and temperature changes. However, sludge granulation cannot be guaranteed on every type of industrial wastewater. Especially in the last two decades, various types of high-rate anaerobic reactor configurations have been developed that are less dependent on the presence of granular sludge, and many of them are currently successfully applied for the treatment of various kinds of industrial wastewaters worldwide. This study discusses the evolution of anaerobic sludge bed technology for the treatment of industrial wastewaters in the last four decades, focusing on granular sludge bed systems.
Vardan Khachatryan1, Albert M. Sirunyan1, Armen Tumasyan1, Wolfgang Adam +2195 more•Institutions (176)
TL;DR: In this article, the authors used a large extra dimensions model and a quark and lepton compositeness model with a left-left isoscalar contact interaction to search for both narrow resonances and broad deviations from standard model predictions.
Abstract: Dimuon and dielectron mass spectra, obtained from data resulting from proton-proton collisions at 8 TeV and recorded by the CMS experiment, are used to search for both narrow resonances and broad deviations from standard model predictions. The data correspond to an integrated luminosity of 20.6 (19.7) fb^(−1) for the dimuon (dielectron) channel. No evidence for non-standard-model physics is observed and 95% confidence level limits are set on parameters from a number of new physics models. The narrow resonance analyses exclude a Sequential Standard Model Z'_(SSM) resonance lighter than 2.90 TeV, a superstring-inspired Z'_ψ lighter than 2.57 TeV, and Randall-Sundrum Kaluza-Klein gravitons with masses below 2.73, 2.35, and 1.27 TeV for couplings of 0.10, 0.05, and 0.01, respectively. A notable feature is that the limits have been calculated in a model-independent way to enable straightforward reinterpretation in any model predicting a resonance structure. The observed events are also interpreted within the framework of two non-resonant analyses: one based on a large extra dimensions model and one based on a quark and lepton compositeness model with a left-left isoscalar contact interaction. Lower limits are established on MS, the scale characterizing the onset of quantum gravity, which range from 4.9 to 3.3 TeV, where the number of additional spatial dimensions varies from 3 to 7. Similarly, lower limits on Λ, the energy scale parameter for the contact interaction, are found to be 12.0 (15.2) TeV for destructive (constructive) interference in the dimuon channel and 13.5 (18.3) TeV in the dielectron channel.
Vardan Khachatryan1, Albert M. Sirunyan1, Armen Tumasyan1, Wolfgang Adam +2319 more•Institutions (149)
TL;DR: In this paper, a 19.7 inverse femtobarn sample of proton-proton collisions at 8 TeV was collected with the CMS detector at the CERN LHC.
Vardan Khachatryan, Albert M. Sirunyan, Armen Tumasyan, Wolfgang Adam1 +2205 more•Institutions (182)
TL;DR: In this paper, a model-independent search for a narrow resonance produced in proton-proton collisions at square root(s) = 8 TeV and decaying to a pair of 125 GeV Higgs bosons that in turn each decays into bottom quark-antiquark pairs is performed by the CMS experiment at the LHC.
TL;DR: The Caco-2 cell line, a human intestinal epithelial cell model derived from a colon carcinoma, has been proven to be a good alternative to animal studies for predicting intestinal absorption of anthocyanins and is critically discussed.
Abstract: Anthocyanins from different plant sources have been shown to possess health beneficial effects against a number of chronic diseases. To obtain any influence in a specific tissue or organ, these bioactive compounds must be bioavailable, i.e., effectively absorbed from the gut into the circulation and transferred to the appropriate location within the body while still maintaining their bioactivity. One of the key factors affecting the bioavailability of anthocyanins is their transport through the gut epithelium. The Caco-2 cell line, a human intestinal epithelial cell model derived from a colon carcinoma, has been proven to be a good alternative to animal studies for predicting intestinal absorption of anthocyanins. Studies investigating anthocyanin absorption by Caco-2 cells report very low absorption of these compounds. However, the bioavailability of anthocyanins may be underestimated since the metabolites formed in the course of digestion could be responsible for the health benefits associated with anthocyanins. In this review, we critically discuss recent findings reported on the anthocyanin absorption and metabolism by human intestinal Caco-2 cells.
Vardan Khachatryan, Albert M. Sirunyan, Armen Tumasyan, Wolfgang Adam1 +2259 more•Institutions (145)
TL;DR: In this article, a systematic study of the factorization of long-range azimuthal twoparticle correlations into a product of single-particle anisotropies is presented as a function of pT and nu of both particles.
Abstract: A systematic study of the factorization of long-range azimuthal two-particle correlations into a product of single-particle anisotropies is presented as a function of pT and nu of both particles and as a function of the particle multiplicity in PbPb and pPb collisions. The data were taken with the CMS detector for PbPb collisions at root sNN = 2.76 TeV and pPb collisions at root sNN = 5.02 TeV, covering a very wide range of multiplicity. Factorization is observed to be broken as a function of both particle pT and nu. When measured with particles of different pT, the magnitude of the factorization breakdown for the second Fourier harmonic reaches 20% for very central PbPb collisions but decreases rapidly as the multiplicity decreases. The data are consistent with viscous hydrodynamic predictions, which suggest that the effect of factorization breaking is mainly sensitive to the initial-state conditions rather than to the transport properties (e.g., shear viscosity) of the medium. The factorization breakdown is also computed with particles of different nu. The effect is found to be weakest for mid-central PbPb events but becomes larger for more central or peripheral PbPb collisions, and also for very-high-multiplicity pPb collisions. The nu-dependent factorization data provide new insights to the longitudinal evolution of the medium formed in heavy ion collisions.
TL;DR: In this article, three nonparametric statistical tests, the Mann-Kendall, Spearman rho, and Sen's T, were applied to estimate the trends in the annual and seasonal time series of temperature, precipitation, and streamflow at 95 stations throughout the basin.
Abstract: The drawdown trend of the water level in Urmia Lake poses a serious problem for northwestern Iran which has had negative impacts on agriculture and industry. This research investigated likely causes of the predicament by estimating trends in the time series of hydroclimatic variables of the basin. Three non-parametric statistical tests, the Mann–Kendall, Spearman rho, and Sen’s T, were applied to estimate the trends in the annual and seasonal time series of temperature, precipitation, and streamflow at 95 stations throughout the basin. The Theil–Sen method was also used to estimate the slopes of trend lines of annual time series. The results showed a significant increasing trend of temperature throughout the basin and an area-specific precipitation trend. The tests also confirmed a general decreasing trend in the basin streamflow that was more pronounced in the downstream stations. The annual trend line slope was found to be from 0.02 to 0.14 °C/year, −7.5 to 3.8 mm/year, and −0.01 to −0.4 m3/s/year for temperature, precipitation, and streamflow, respectively. The homogeneity of the monthly trends was also evaluated using the Van Belle and Hughes tests as confirmation. Temporal analyses of the trends for the temperature and streamflow of the basin detected significant increasing trends beginning in the mid-1980s and 1990s. The correlations between streamflow and climate variables (temperature and precipitation) were detected by Pearson’s test. The results showed that the streamflow in Urmia Lake basin is more sensitive to changes in temperature than precipitation. In general, the decline in the lake water level can be related to both the increase of temperature in the basin and an improvement in over-exploitation of the water resources.
TL;DR: In this article, a new lithostratigraphy scheme has been compiled for the Western Black Sea Basin and a new geological history scheme from Middle Jurassic till Neogene is suggested for the entire Black Sea Region.
TL;DR: In the early Palaeozoic, a Pontide terrane collided and amalgamated to the core of Laurasia, as part of the Avalonia-Laurasia collision as discussed by the authors.
Abstract: The Black Sea region comprises Gondwana-derived continental blocks and oceanic subduction complexes accreted to Laurasia. The core of Laurasia is made up of an Archaean–Palaeoproterozoic shield, whereas the Gondwana-derived blocks are characterized by a Neoproterozoic basement. In the early Palaeozoic, a Pontide terrane collided and amalgamated to the core of Laurasia, as part of the Avalonia–Laurasia collision. From the Silurian to Carboniferous, the southern margin of Laurasia was a passive margin. In the late Carboniferous, a magmatic arc, represented by part of the Pontides and the Caucasus, collided with this passive margin with the Carboniferous eclogites marking the zone of collision. This Variscan orogeny was followed by uplift and erosion during the Permian and subsequently by Early Triassic rifting. Northward subduction under Laurussia during the Late Triassic resulted in the accretion of an oceanic plateau, whose remnants are preserved in the Pontides and include Upper Triassic eclogites. The C...
TL;DR: A review of the photochemistry of thioxanthone-based systems and their use in different modes of photo-initiated polymerizations is presented in this paper, where the development of various photoinitiating systems along with an understanding of their mechanistic behavior has been elucidated previously.
Vardan Khachatryan, Albert M. Sirunyan, Armen Tumasyan, Wolfgang Adam1 +2115 more•Institutions (146)
TL;DR: In this article, upper limits on the product of the cross section and branching fraction of such a signal are presented as a function of the long-lived particle's mean proper decay length.
Abstract: A search is performed for long-lived particles that decay into final states that include a pair of electrons or a pair of muons. The experimental signature is a distinctive topology consisting of a pair of charged leptons originating from a displaced secondary vertex. Events corresponding to an integrated luminosity of 19.6 (20.5) inverse femtobarns in the electron (muon) channel were collected with the CMS detector at the CERN LHC in proton-proton collisions at sqrt(s) = 8 TeV. No significant excess is observed above standard model expectations. Upper limits on the product of the cross section and branching fraction of such a signal are presented as a function of the long-lived particle's mean proper decay length. The limits are presented in an approximately model-independent way, allowing them to be applied to a wide class of models yielding the above topology. Over much of the investigated parameter space, the limits obtained are the most stringent to date. In the specific case of a model in which a Higgs boson in the mass range 125-1000 GeV decays into a pair of long-lived neutral bosons in the mass range 20-350 GeV, each of which can then decay to dileptons, the upper limits obtained are typically in the range 0.2-10 fb for mean proper decay lengths of the long-lived particles in the range 0.01-100 cm. In the case of the lowest Higgs mass considered (125 GeV), the limits are in the range 2-50 fb. These limits are sensitive to Higgs boson branching fractions as low as 1E-4.
TL;DR: In this article, the role of mixed oxides in depolymerization of soda lignin in supercritical ethanol was investigated, and the results showed that the mixture of Cu and basic sites catalyzes Guerbet and esterification reactions.
Abstract: We investigated the role of Cu–Mg–Al mixed oxides in depolymerization of soda lignin in supercritical ethanol. A series of mixed oxides with varying Cu content and (Cu+Mg)/Al ratio were prepared. The optimum catalyst containing 20 wt % Cu and having a (Cu+Mg)/Al ratio of 4 yielded 36 wt % monomers without formation of char after reaction at 340 °C for 4 h. Comparison with Cu/MgO and Cu/γ-Al2O3 catalysts emphasized the excellent performance of Cu–Mg–Al oxides. These mixed oxides catalyze the reaction between formaldehyde and ethanol, which limits polymerization reactions between phenolic products and formaldehyde. The combination of Cu and basic sites catalyzes the associated Guerbet and esterification reactions. These reactions also protect lignin side-chains (e.g., aldehyde groups). Lewis acid sites of the catalyst, mainly Cu and Al cations, catalyze C- and O-alkylation reactions that protect phenolic products and phenolic moieties in lignin oligomers. Hydrogen produced by dehydrogenation reactions is in...