Search

A measurement of the top quark mass (M-t) in the dileptonic t (t) over bar decay channel is performed using data from proton-proton collisions at a center-of-mass energy of 8 TeV. The data was recorded by the CMS experiment at the LHC and corresponds to an integrated luminosity of 19.7 +/- 0.5 fb(-1). Events are selected with two oppositely charged leptons (l = e, mu) and two jets identified as originating from b quarks. The analysis is based on three kinematic observables whose distributions are sensitive to the value of Mt. An invariant mass observable, M-bl, and a stransverse mass observable, M-T2, are employed in a simultaneous fit to determine the value of M-t and an overall jet energy scale factor (JSF). A complementary approach is used to construct an invariant mass observable, M-blv, that is combined with M-T2 to measure M-t. The shapes of the observables, along with their evolutions in M-t and JSF, are modeled by a nonparametric Gaussian process regression technique. The sensitivity of the observables to the value of M-t is investigated using a Fisher information density method. The top quark mass is measured to be 172.22 +/- 0.18(stat)(-0.93)(+0.89) (syst) GeV.

In the original paper, figure 10 was incorrect. The correct figure is shown above. Link to Erratum 2: [https://vinar.vin.bg.ac.rs/handle/123456789/1921] Link to the original article: [https://vinar.vin.bg.ac.rs/handle/123456789/10985]

Pair production of gamma(1S) mesons is observed at the LHC in proton-proton collisions at root s = 8 TeV by the CMS experiment in a data sample corresponding to an integrated luminosity of 20.7 fb(-1). Both gamma(1S) candidates are fully reconstructed via their decays to mu(+) mu(-). The fiducial acceptance region is defined by an absolute gamma(1S) rapidity smaller than 2.0. The fiducial cross section for the production of gamma(1S) pairs, assuming that both mesons decay isotropically, is measured to be 68.8 +/- 12.7 (stat) +/- 7.4 (syst) +/- 2.8 (B) pb, where the third uncertainty comes from the uncertainty in the branching fraction of gamma(1S) decays to mu(+) mu(-). Assuming instead that the gamma(1S) mesons are produced with different polarizations leads to variations in the measured cross section in the range from 38% to +36%.

A measurement of the top quark pair production () cross section in proton-proton collisions at the centre-of-mass energy of 8 is presented using data collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 19.6. This analysis is performed in the decay channels with one isolated, high transverse momentum electron or muon and at least four jets, at least one of which is required to be identified as originating from hadronization of a b quark. The calibration of the jet energy scale and the efficiency of b jet identification are determined from data. The measured cross section is . This measurement is compared with an analysis of 7 data, corresponding to an integrated luminosity of 5.0, to determine the ratio of 8 to 7 cross sections, which is found to be . The measurements are in agreement with QCD predictions up to next-to-next-to-leading order.

A search for dark matter particles is performed using events with large missing transverse momentum, at least one energetic jet, and no leptons, in proton-proton collisions at root S = 13TeV collected with the CMS detector at the LHC. The data sample corresponds to an integrated luminosity of 12.9 fb(-1). The search includes events with jets from the hadronic decays of a W or Z boson. The data are found to be in agreement with the predicted background contributions from standard model processes. The results are presented in terms of simpli fi ed models in which dark matter particles are produced through interactions involving a vector, axial-vector, scalar, or pseudoscalar mediator. Vector and axial-vector mediator particles with masses up to 1.95TeV, and scalar and pseudoscalar mediator particles with masses up to 100 and 430 GeV respectively, are excluded at 95% con fi dence level. The results are also interpreted in terms of the invisible decays of the Higgs boson, yielding an observed (expected) 95% con fi dence level upper limit of 0.44 (0.56) on the corresponding branching fraction. The results of this search provide the strongest constraints on the dark matter pair production cross section through vector and axial-vector mediators at a particle collider. When compared to the direct detection experiments, the limits obtained from this search provide stronger constraints for dark matter masses less than 5, 9, and 550 GeV, assuming vector, scalar, and axial-vector mediators, respectively. The search yields stronger constraints for dark matter masses less than 200 GeV, assuming a pseudoscalar mediator, when compared to the indirect detection results from Fermi-LAT.

Jet charge is an estimator of the electric charge of a quark, antiquark, or gluon initiating a jet. It is based on the momentum-weighted sum of the electric charges of the jet constituents. Measurements of three charge observables of the leading jet in transverse momentum pT are performed with dijet events. The analysis is carried out with data collected by the CMS experiment at the CERN LHC in proton-proton collisions at root s = 8 TeV corresponding to an integrated luminosity of 19.7 fb(-1). The results are presented as a function of the pT of the leading jet and compared to predictions from leading and next-to-leading-order event generators combined with parton showers. Measured jet charge distributions, unfolded for detector effects, are reported, which expand on previous measurements of the jet charge average and standard deviation in pp collisions.

Searches are presented for direct production of top or bottom squark pairs in proton-proton collisions at the CERN LHC. Two searches, based on complementary techniques, are performed in all-jet final states that are characterized by a significant imbalance in transverse momentum. An additional search requires the presence of a charged lepton isolated from other activity in the event. The data were collected in 2015 at a centre-of-mass energy of 13 TeV with the CMS detector and correspond to an integrated luminosity of 2.3 fb(-1). No statistically significant excess of events is found beyond the expected contribution from standard model processes. Exclusion limits are set in the context of simplified models of top or bottom squark pair production. Models with top and bottom squark masses up to 830 and 890 GeV, respectively, are probed for light neutralinos. For models with top squark masses of 675 GeV, neutralino masses up to 260 GeV are excluded at 95% confidence level.

A statistical combination of searches is presented for massive resonances decaying to WW, WZ, ZZ, WH, and ZH boson pairs in proton-proton collision data collected by the CMS experiment at the LHC. The data were taken at centre-of-mass energies of 8 and 13TeV, corresponding to respective integrated luminosities of 19.7 and up to 2.7 fb(-1). The results are interpreted in the context of heavy vector triplet and singlet models that mimic properties of composite-Higgs models predicting W and Z bosons decaying to WZ, WW, WH, and ZH bosons. A model with a bulk graviton that decays into WW and ZZ is also considered. This is the first combined search for WW, WZ, WH, and ZH resonances and yields lower limits on masses at 95% confidence level for W and Z singlets at 2.3 TeV, and for a triplet at 2.4TeV. The limits on the production cross section of a narrow bulk graviton resonance with the curvature scale of the warped extra dimension (K)over-tilde = 0.5, in the mass range of 0.6 to 4.0TeV, are the most stringent published to date. (c) 2017 The Author(s). Published by Elsevier B.V.

A measurement of the differential cross sections for a W boson produced in association with jets in the muon decay channel is presented. The measurement is based on 13 TeV proton-proton collision data corresponding to an integrated luminosity of 2.2 fb(-1), recorded by the CMS detector at the LHC. The cross sections are reported as functions of jet multiplicity, jet transverse momentum pT, jet rapidity, the scalar pT sum of the jets, and angular correlations between the muon and each jet for different jet multiplicities. The measured cross sections are in agreement with predictions that include multileg leading-order (LO) and next-to-LO matrix element calculations interfaced with parton showers, as well as a next-to-next-to-LO calculation for the W boson and one jet production.

A search is performed for anomalous interactions of the recently discovered Higgs boson using matrix element techniques with the information from its decay to four leptons and from associated Higgs boson production with two quark jets in either vector boson fusion or associated production with a vector boson. The data were recorded by the CMS experiment at the LHC at a center-of-mass energy of 13 TeV and correspond to an integrated luminosity of 38.6 fb(-1). They are combined with the data collected at center-of-mass energies of 7 and 8 TeV, corresponding to integrated luminosities of 5.1 and 19.7 fb(-1), respectively. All observations are consistent with the expectations for the standard model Higgs boson. (C) 2017 The Author. Published by Elsevier B.V.

A search for the production of heavy resonances decaying into top quark-antiquark pairs is presented. The analysis is performed in the lepton+jets and fully hadronic channels using data collected in proton-proton collisions at root s = 13 TeV using the CMS detector at the LHC, corresponding to an integrated luminosity of 2.6 fb(-1). The selection is optimized for massive resonances, where the top quarks have large Lorentz boosts. No evidence for resonant t (t) over bar production is found in the data, and upper limits on the production cross section of heavy resonances are set. The exclusion limits for resonances with masses above 2 TeV are significantly improved compared to those of previous analyses at root s = 8 TeV.

A search for a signal consistent with the type-III seesaw mechanism in events with three or more electrons or muons is presented. The data sample consists of proton-proton collisions at root s = 13 TeV collected by the CMS experiment at the LHC in 2016 and corresponds to an integrated luminosity of 35.9 fb(-1). Selection criteria based on the number of leptons and the invariant mass of oppositely charged lepton pairs are used to distinguish the signal from the standard model background. The observations are consistent with the expectations from standard model processes. The results are used to place limits on the production of heavy fermions of the type-III seesaw model as a function of the branching ratio to each lepton flavor. In the scenario of equal branching fractions to each lepton flavor, heavy fermions with masses below 840 GeV are excluded. This is the most sensitive probe to date of the type-III seesaw mechanism.

A search is presented for massive spin-1 Z resonances decaying to a top quark and a heavy vector-like top quark partner T. The search is based on a 2.6 fb(-1) sample of proton-proton collisions at 13TeV collected with the CMS detector at the LHC. The analysis is optimized for final states in which the T quark decays to a W boson and a bottom quark. The focus is on all-jet final states in which both the W boson and the top quark decay into quarks that evolve into jets. The decay products of the top quark and of the W boson are assumed to be highly Lorentz-boosted and cannot be reconstructed as separate jets, but are instead reconstructed as merged, wide jets. Techniques for the identification of jet substructure and jet flavour are used to distinguish signal from background events. Several models for Z bosons decaying to T quarks are excluded at 95% confidence level, with upper limits on the cross section ranging from 0.13 to 10 pb, depending on the chosen hypotheses. This is the first search for a neutral spin-1 heavy resonance decaying to a top quark and a vector-like T quark in the all-hadronic final state.

The WZ production cross section is measured by the CMS experiment at the CERN LHC in proton proton collision data samples corresponding to integrated luminosities of 4.9 fb(-1) collected at root s = 7 TeV, and 19.6fb(-1) at root s = 8 TeV. The measurements are performed using the fully-leptonic WZ decay modes with electrons and muons in the final state. The measured cross sections for 71 LT m(Z) LT 111 GeV are sigma (pp - GT WZ; root s = 7 TeV) = 20.14 +/- 1.32 (stat)+/- 0.38 (theo)+/- 1.06 (exp)+/- 0.44 (lumi) pb and sigma (pp - GT WZ; root s = 8 TeV) = 24.09 +/- 0.87 (stat) 0.80 (theo) +/- 1.40 (exp) +/- 0.63 (lumi) pb. Differential cross sections with respect to the Z boson p(T), the leading jet p(T), and the number of jets are obtained using the root s = 8 TeV data. The results are consistent with standard model predictions and constraints on anomalous triple gauge couplings are obtained.

A search for physics beyond the standard model in final states with at least one photon, large transverse momentum imbalance, and large total transverse event activity is presented. Such topologies can be produced in gauge-mediated supersymmetry models in which pair-produced gluinos or squarks decay to photons and gravitinos via shortlived neutralinos. The data sample corresponds to an integrated luminosity of 35.9 fb(-1) of proton-proton collisions at root s = 13TeV recorded by the CMS experiment at the LHC in 2016. No significant excess of events above the expected standard model background is observed. The data are interpreted in simplified models of gluino and squark pair production, in which gluinos or squarks decay via neutralinos to photons. Gluino masses of up to 1.50-2.00TeV and squark masses up to 1.30-1.65TeV are excluded at 95% confidence level, depending on the neutralino mass and branching fraction.

A search for a light pseudoscalar Higgs boson (A) produced in association with bottom quarks and decaying into a muon pair is reported. The search uses 19.7 fb(-1) of proton-proton collisions at a center-of-mass energy of 8TeV, collected by the CMS experiment. No signal is observed in the dimuon mass range from 25 to 60 GeV. Upper limits on the cross section times branching fraction, sigma(pp - GT b $(b) over bar $A) B(A - GT mu mu), are set.

A data sample of events from proton-proton collisions with two isolated same-sign leptons, missing transverse momentum, and jets is studied in a search for signatures of new physics phenomena by the CMS Collaboration at the LHC. The data correspond to an integrated luminosity of 35.9 fb(-1), and a center-of-mass energy of 13 TeV. The properties of the events are consistent with expectations from standard model processes, and no excess yield is observed. Exclusion limits at 95% confidence level are set on cross sections for the pair production of gluinos, squarks, and same-sign top quarks, as well as top-quark associated production of a heavy scalar or pseudoscalar boson decaying to top quarks, and on the standard model production of events with four top quarks. The observed lower mass limits are as high as 1500 GeV for gluinos, 830 GeV for bottom squarks. The excluded mass range for heavy (pseudo) scalar bosons is 350-360 (350-410) GeV. Additionally, model-independent limits in several topological regions are provided, allowing for further interpretations of the results.

A search is performed for Higgs-boson-mediated flavor-changing neutral currents in the decays of top quarks. The search is based on proton-proton collision data corresponding to an integrated luminosity of 19.7 fb(-1) at a center-of-mass energy of 8 TeV collected with the CMS detector at the LHC. Events in which a top quark pair is produced with one top quark decaying into a charm or up quark and a Higgs boson (H), and the other top quark decaying into a bottom quark and a W boson are selected. The Higgs boson in these events is assumed to subsequently decay into either dibosons or difermions. No signi fi cant excess is observed above the expected standard model background, and an upper limit at the 95% con fi dence level is set on the branching fraction B (t - GT Hc) of 0.40% and B (t - GT Hu) of 0.55%, where the expected upper limits are 0.43% and 0.40%, respectively. These results correspond to upper limits on the square of the flavor-changing Higgs boson Yukawa couplings vertical bar lambda(H)(tc)vertical bar(2) LT 6 . 9 x 10(-3) and vertical bar lambda(H)(tu)vertical bar(2) LT 9 . 8 x 10(-3).

Results are reported from a search for supersymmetric particles in protonproton collisions in the final state with a single, high transverse momentum lepton; multiple jets, including at least one b-tagged jet; and large missing transverse momentum. The data sample corresponds to an integrated luminosity of 2: 3 fb(-1) at root s = 13TeV, recorded by the CMS experiment at the LHC. The search focuses on processes leading to high jet multiplicities, such as gluino pair production with (g) over tilde - GT t (t) over bar(chi) over tilde (0)(1) . The quantity M-J, defined as the sum of the masses of the large-radius jets in the event, is used in conjunction with other kinematic variables to provide discrimination between signal and background and as a key part of the background estimation method. The observed event yields in the signal regions in data are consistent with those expected for standard model backgrounds, estimated from control regions in data. Exclusion limits are obtained for a simplified model corresponding to gluino pair production with three-body decays into top quarks and neutralinos. Gluinos with a mass below 1600 GeV are excluded at a 95% confidence level for scenarios with low (chi) over tilde (0)(1) mass, and neutralinos with a mass below 800 GeV are excluded for a gluino mass of about 1300 GeV. For models with two-body gluino decays producing on-shell top squarks, the excluded region is only weakly sensitive to the top squark mass.

A measurement of the cross section for top quark-antiquark (t (t) over bar) pairs produced in association with a photon in proton-proton collisions at root s = 8TeV is presented. The analysis uses data collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 19.7 fb(1). The signal is de fined as the production of a t (t) over bar pair in association with a photon having a transverse energy larger than 25 GeV and an absolute pseudorapidity smaller than 1.44. The measurement is performed in the fiducial phase space corresponding to the semileptonic decay chain of the t (t) over bar pair, and the cross section is measured relative to the inclusive t (t) over bar pair production cross section. The fiducial cross section for associated t (t) over bar pair and photon production is found to be 127 +/- 27 (stat + syst) fb per semileptonic final state. The measured value is in agreement with the theoretical prediction.

A measurement of the top quark mass is reported in events containing a single top quark produced via the electroweak t channel. The analysis is performed using data from proton-proton collisions collected with the CMS detector at the LHC at a centre-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 19.7 fb(-1). Top quark candidates are reconstructed from their decay to a W boson and a b quark, with the W boson decaying leptonically to a muon and a neutrino. The final state signature and kinematic properties of single top quark events in the t channel are used to enhance the purity of the sample, suppressing the contribution from top quark pair production. A fit to the invariant mass distribution of reconstructed top quark candidates yields a value of the top quark mass of 172.95 +/- 0.77 (stat)(-0.93)(+0.97) (syst) GeV. This result is in agreement with the current world average, and represents the first measurement of the top quark mass in event topologies not dominated by top quark pair production, therefore contributing to future averages with partially uncorrelated systematic uncertainties and a largely uncorrelated statistical uncertainty.

This paper presents a comparative analysis of studies for pre-school teachers and teachers in Serbia and Bulgaria. The mentioned studies are being prepared, planned, organized and realized in Serbia and Bulgaria by the Bologna model. Upon completion of bachelor studies, students receive a diploma with 240 ESBP with the obligation to enroll master academic studies. Nevertheless, studies for pre-school teachers and teachers in Bulgaria differ significantly. Unlike Serbia, where they are two separate study programs: 1) teachers in pre-school institutions and 2) class teaching, in Bulgaria it is a joint study program, which is generally harmonized at all universities. There is only a terminological difference in the title of the study program, such as at the Sofia University of Sv. Kliment Ohridski in Sofia - class and preschool pedagogy; St. Gregory's univ. Cyril and Methodius in Veliko Tarnovo - pre-school and initial school pedagogy; Southwestern University Neofit Rilski in Blagoevgrad - pedagogy for pre-school and class teaching. A significant difference is reflected in the curriculum for teachers and pre-school teachers in Serbia and Bulgaria. Without going into more detail in the presentation of studies for pre-school teachers and teachers in Serbia, the paper presents a joint study program for pre-school teachers and teachers in Bulgaria, and then a comparative analysis of study programs for pre-school teachers and teachers in Serbia and Bulgaria.

Normalized double-differential cross sections for top quark pair (t (t) over bar) production are measured in pp collisions at a centre-of-mass energy of 8 TeV with the CMS experiment at the LHC. The analyzed data correspond to an integrated luminosity of 19.7 fb(-1). The measurement is performed in the dilepton e(+/-)mu(+/-) final state. The tt cross section is determined as a function of various pairs of observables characterizing the kinematics of the top quark and tt system. The data are compared to calculations using perturbative quantum chromodynamics at next-to-leading and approximate next-to-next-to-leading orders. They are also compared to predictions of Monte Carlo event generators that complement fixed-order computations with parton showers, hadronization, and multiple-parton interactions. Overall agreement is observed with the predictions, which is improved when the latest global sets of proton parton distribution functions are used. The inclusion of the measured tt cross sections in a fit of parametrized parton distribution functions is shown to have significant impact on the gluon distribution.

Single top quark events produced in the t channel are used to set limits on anomalous Wtb couplings and to search for top quark flavour-changing neutral current (FCNC) interactions. The data taken with the CMS detector at the LHC in proton-proton collisions at and 8 TeV correspond to integrated luminosities of 5.0 and 19.7 fb(-1), respectively. The analysis is performed using events with one muon and two or three jets. A Bayesian neural network technique is used to discriminate between the signal and backgrounds, which are observed to be consistent with the standard model prediction. The 95% confidence level (CL) exclusion limits on anomalous right-handed vector, and left- and right-handed tensor Wtb couplings are measured to be vertical bar f (V) (R) vertical bar LT 0.16,aEuro,vertical bar f (T) (L) vertical bar LT 0.057, and - 0.049 LT f (T) (R) LT 0.048, respectively. For the FCNC couplings kappa (tug) and kappa (tcg), the 95% CL upper limits on coupling strengths are vertical bar kappa (tug)vertical bar/I GT LT 4.1 x 10(- 3) TeV-1 and vertical bar kappa (tcg)vertical bar/Lambda LT 1.8 x 10(- 2) TeV-1, where I GT is the scale for new physics, and correspond to upper limits on the branching fractions of 2.0 x 10(-5) and 4.1 x 10(-4) for the decays t - GT ug and t - GT cg, respectively.

An inclusive search is performed for supersymmetry in final states containing jets and an apparent imbalance in transverse momentum, (p) over right arrow (miss)(T),due to the production of unobserved weakly interacting particles in pp collisions at a centre-of-mass energy of 8 TeV. The data, recorded with the CMS detector at the CERN LHC, correspond to an integrated luminosity of 18.5fb(-1). The dimensionless kinematic variable alpha(T) is used to discriminate between events with genuine (p) over right arrow (miss)(T)associated with unobserved particles and spurious values of (p) over right arrow (miss)(T) Tarising from jet energy mismeasurements. No excess of event yields above the expected standard model backgrounds is observed. The results are interpreted in terms of constraints on the parameter space of several simplified models of supersymmetry that assume the pair production of top squarks. The search provides sensitivity to a broad range of top squark ((t) over tilde) decay modes, including the two-body decay (t)over tilde GT - GT c (chi) over tilde (0)(1),where c is a charm quark (chi) over tilde (0)(1) and is the lightest neutralino, as well as the four-body decay (t)over tilde GT - GT bf (f) over bar (chi) over bar (0)(1),where b is a bottom quark and f and (f) over bar are fermions produced in the decay of an intermediate off-shell W boson. These modes dominate in scenarios in which the top squark and lightest neutralino are nearly degenerate in mass. For these modes, top squarks with masses as large as 260 and 225 GeV are excluded, respectively, for the two-and four-body decays. (C) 2017 The Author. Published by Elsevier B.V.

The results of a first search for CP violation in the production and decay of top quark-antiquark (t (t) over bar) pairs are presented. The search is based on asymmetries in T-odd, triple-product correlation observables, where T is the time-reversal operator. The analysis uses a sample of proton-proton collisions at root s = 8 TeV collected by the CMS experiment, corresponding to an integrated luminosity of 19.7fb(-1). Events are selected having one electron or muon and at least four jets. The T-odd observables are measured using four-momentum vectors associated with t (t) over bar production and decay. The measured asymmetries exhibit no evidence for CP-violating effects, consistent with the expectation from the standard model.

Cross sections for the production of a Z boson in association with jets in proton-proton collisions at a centre-of-mass energy of root s = 8 TeV are measured using a data sample collected by the CMS experiment at the LHC corresponding to 19.6 fb(-1). Differential cross sections are presented as functions of up to three observables that describe the jet kinematics and the jet activity. Correlations between the azimuthal directions and the rapidities of the jets and the Z boson are studied in detail. The predictions of a number of multileg generators with leading or next-to-leading order accuracy are compared with the measurements. The comparison shows the importance of including multi-parton contributions in the matrix elements and the improvement in the predictions when nextto- leading order terms are included.

A search is presented for decays beyond the standard model of the 125 GeV Higgs bosons to a pair of light bosons, based on models with extended scalar sectors. Light boson masses between 5 and 62.5 GeV are probed in final states containing four tau leptons, two muons and two b quarks, or two muons and two tau leptons. The results are from data in proton-proton collisions corresponding to an integrated luminosity of 19.7 fb(-1), accumulated by the CMS experiment at the LHC at a center-of-mass energy of 8TeV. No evidence for such exotic decays is found in the data. Upper limits are set on the product of the cross section and branching fraction for several signal processes. The results are also compared to predictions of two-Higgs-doublet models, including those with an additional scalar singlet.

A measurement of the t (t) over bar production cross section at root s = 13 TeV is presented using proton-proton collisions, corresponding to an integrated luminosity of 2.2 fb(-1), collected with the CMS detector at the LHC. Final states with one isolated charged lepton (electron or muon) and at least one jet are selected and categorized according to the accompanying jet multiplicity. From a likelihood fit to the invariant mass distribution of the isolated lepton and a jet identified as coming from the hadronization of a bottom quark, the cross section is measured to be sigma(tt) = 888 +/- 2; (stat) (+26)(-28) (syst) +/- 20 (lumi) pb, in agreement with the standard model prediction. Using the expected dependence of the cross section on the pole mass of the top quark (m(t)), the value of m(t) is found to be 170:6 +/- 2:7 GeV.

The production cross section of a W boson in association with two b jets is measured using a sample of proton-proton collisions at root s = 8 TeV collected by the CMS experiment at the CERN LHC. The data sample corresponds to an integrated luminosity of 19.8 fb(-1). The W bosons are reconstructed via their leptonic decays, W - GT l(v) where l = mu or e. The fiducial region studied contains exactly one lepton with transverse momentum pT(l) GT 30 GeV and pseudorapidity |eta(l)| LT 2.1, with exactly two b jets with pT GT 25 GeV and |eta(l)| LT 2.4 and no other jets with pT GT 25 GeV and |eta(l)| LT 4.7. The cross section is measured to be sigma(pp - GT W(lv)+b LT (b)over bar GT ) = 0.64 +/- 0.03 (stat) +/- 0.10 (syst) +/- 0.06 (theo) +/- 0.02 (lumi) pb, in agreement with standard model predictions.

This paper presents the results of an empirical research of presence, importance and need of expanding educational content of the cultural heritage of Kosovo and Metohija in nature teaching textbooks in elementary grades. The study is based on the assumption that the educational content on the cultural heritage of Kosovo and Metohija in the elementary grades is significant for later learning and understanding of the entire cultural heritage of Serbia. However, in the books of nature these contents are not represented sufficiently, wherefore they need to be extended.In order to determine this assumption, 107 students of the Teacher Training Faculty in Prizren, in October 2016, took part in the research presented in this paper. Data collected by Scaler NSKNKM (α = .783), were analyzed by descriptive statistics and the analysis of variance. It was found that the largest number of students estimated that the teaching content of the cultural heritage of Kosovo and Metohija are not sufficiently represented in textbooks on nature, according to 86.90%. The analyses of variance showed there was no statistically significant difference in the results of the three groups of students in their estimation of the importance and the necessity of teaching contents on the cultural heritage of Kosovo and Metohija in textbooks of studying nature: F (2; 104) = .093, p = .912. The research results show that the teaching contents about Kosovo and Metohija in the books of nature teaching are under-represented and there is need to expand them (Table 2).

A search for heavy resonances with masses above 1 TeV, decaying to final states containing a vector boson and a Higgs boson, is presented. The search considers hadronic decays of the vector boson, and Higgs boson decays to b quarks. The decay products are highly boosted, and each collimated pair of quarks is reconstructed as a single, massive jet. The analysis is performed using a data sample collected in 2016 by the CMS experiment at the LHC in proton-proton collisions at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb(-1). The data are consistent with the background expectation and are used to place limits on the parameters of a theoretical model with a heavy vector triplet. In the benchmark scenario with mass-degenerate W and Z bosons decaying predominantly to pairs of standard model bosons, for the first time heavy resonances for masses as high as 3.3 TeV are excluded at 95% confidence level, setting the most stringent constraints to date on such states decaying into a vector boson and a Higgs boson.

Background: Oral lichen planus (OLP) is a precancerous lesion which might progress into oral squamous cell cancer (OSCC) in 0-1.2 % of the affected patients. Albeit there are many published studies upon this topic, there are no universally accepted clinical and histopathological criteria which would suggest which patients will develop OSCC. Therefore, the aim of this study was to compare epithelial and sub epithelial FHIT and Bcl-2 expression between patients with OLP, OSCC and healthy oral mucosa.Materials and Methods: Fifty patients with OLP, 20 with OSCC who had histologically confi rmed diagnoses and 20 healthy controls were included in this study. Immuno-histochemical analysis was performed on primary monoclonal antibodies Bcl-2 (Dako, Finland) and FHIT (Zymed Laboratories Inc., USA) were used. Statistical analysis included Kolmogorov-Smirnoff test, χ2 test and Spearman’s correlation. All p values lower than p, Uvod: Oralni lihen planus (OLP) je prekancerozna lezija koji u 0-1,2 % oboljelih može progredirati u oralni karcinom pločastih stanica (OKPS). Premda su objavljeni brojni radovi na ovu temu, ne postoje opće prihvaćeni klinički i patohistološki kriteriji koji bi upućivali na to u kojih će se bolesnika razviti OKPS. Dakle, cilj je ovog istraživanja bio usporediti ekspresiju FHIT i Bcl-2 u epitelu i subepitelu pacijenata s OLP, OKPS te osoba sa zdravom oralnom sluznicom. Materijal i metode: U istraživanje je bilo uključeno pedeset pacijenata s histološki potvrđenom dijagnozom OLP, 20 pacijenata s histološki potvrđenom dijagnozom OKPS te 20 zdravih pacijenata kao kontrolna skupina. Korištene su imunohistokemijske analize na primarnim monoklonim protutijelima Bcl (Dako, Finska) i FHIT (Zymed Laboratories Inc., SAD). U statističkoj analizi korišteni su Kolmogorov-Smirnovljev test, hi kvadrat test i Spearmanov koefi cijent korelacije. P vrijednosti manje od 0.05 su smatrane značajnima. Rezultati: Ekspresija FHIT u epitelu zahvaćenom s OLP i OKPS je značajno smanjena u usporedbi sa zdravom oralnom sluznicom. Međutim, nije nađena značajna razlika u FHIT ekspresiji kod OLP i OKPS. Pacijenti oboljeli od OLP i OKPS imaju značajno pojačanu ekspresiju Bcl-2 u usporedbi s zdravim sudionicima. Nadalje, Bcl-2 ekspresija je značajno veća u pacijenata s OLP, nego u pacijenata s OKPS. Subepitelni infi ltrat u pacijenata s OLP i OKPS pokazuje značajno povećanje Bcl-2 ekspresije u odnosu na zdrave osobe iz kontrolne skupine. Međutim, Bcl-2 ekspresija u upalnom infiltratu je značajno viša u OKPS pacijenata nego li u OLP pacijenata. Zaključak: Gubitak FHIT ekspresije u epitelu sam po sebi nije dovoljan za zloćudnu transformaciju kod pacijenata koji boluju od OLP. Čini se da su za progresiju OLP u OKPS potrebne i druge molekularne promjene. Ekspresija Bcl-2 u upalnom infi ltrate je znakovito visa u bolesnika s OPKS u odnosu na bolesnicke s OLP i zdrave kontrole, ipak, ekspresija bcl-2 u epitelu ne korelira s prekanceroznim (OLP) odnosno lezijama OPKS.

Results are reported from a search for physics beyond the standard model in final states with at least three charged leptons, in any combination of electrons or muons. The data sample corresponds to an integrated luminosity of 2.3 fb(-1) of proton-proton collisions at root s = 13 TeV, recorded by the CMS experiment at the LHC in 2015. Two jets are required in each event, providing good sensitivity to strong production of gluinos and squarks. The search regions, sensitive to a range of different new physics scenarios, are defined using the number of jets tagged as originating from bottom quarks, the sum of the magnitudes of the transverse momenta of the jets, the imbalance in the overall transverse momentum in the event, and the invariant mass of opposite-sign, same-flavor lepton pairs. The event yields observed in data are consistent with the expected background contributions from standard model processes. These results are used to derive limits in terms of R-parity conserving simplified models of supersymmetry that describe strong production of gluinos and squarks. Model-independent limits are presented to facilitate the reinterpretation of the results in a broad range of scenarios for physics beyond the standard model.

A search for the resonant production of high-mass photon pairs is presented. The search focuses on spin-0 and spin-2 resonances with masses between 0.5 and 4.5 TeV, and with widths, relative to the mass, between 1.4 x 10(-4) and 5.6 x 10(-2). The data sample corresponds to an integrated luminosity of 12.9 fb(-1) of proton-proton collisions collected with the CMS detector in 2016 at a center-of-mass energy of 13 TeV. No significant excess is observed relative to the standard model expectation. The results of the search are combined statistically with those previously obtained in 2012 and 2015 at root s = 8 and 13 TeV, respectively, corresponding to integrated luminosities of 19.7 and 3.3 fb(-1), to derive exclusion limits on scalar resonances produced through gluon-gluon fusion, and on Randall-Sundrum gravitons. The lower mass limits for Randall-Sundrum gravitons range from 1.95 to 4.45 TeV for coupling parameters between 0.01 and 0.2. These are the most stringent limits on Randall-Sundrum graviton production to date. (C) 2017 The Author. Published by Elsevier B.V.

A measurement is presented of the cross section for the electroweak production of a Z boson and a photon in association with two jets in proton-proton collisions at root s = 8 TeV. The Z bosons are identified through their decays to electron or muon pairs. The measurement is based on data collected with the CMS detector corresponding to an integrated luminosity of 19.7 fb(-1). The electroweak contribution has a significance of 3.0 standard deviations, and the measured fiducial cross section is 1.86(-0.75)(+0.90)(stat)(-0.26)(+0.34)(syst) +/- 0.05(lumi) fb, while the summed electroweak and quantum chromodynamic total cross section in the same region is observed to be 5.94(-1.35)(+1.53) (stat)(-0.37)(+0.43)(syst) +/- 0.13(lumi) fb. Both measurements are consistent with the leading-order standard model predictions. Limits on anomalous quartic gauge couplings are set based on the Z gamma mass distribution. (C) 2017 The Author. Published by Elsevier B.V.

The CMS Collaboration presents the first measurement of the differential cross section of jets from charm quarks produced in proton-lead (pPb) collisions at a nucleon-nucleon center-of-mass energy of root sNN= 5.02 TeV, as well as results from charm quark jets in proton-proton (pp) collisions at root s=2.76and 5.02TeV. By comparing the yields of the pPb and pp collision systems at the same energy, a nuclear modification factor for charm jets from 55 to 400GeV/cin pPb collisions at root sNN=5.02 TeV of R-pA= 0.92 +/- 0.07 (stat) +/- 0.11(syst) is obtained. This is consistent with an absence of final-state energy loss for charm quarks in pPb collisions. In addition, the fraction of jets coming from charm quarks is found to be consistent with that predicted by PYTHIA 6 for pp collisions at root s=2.76 and 5.02TeV, and is independent of the jet transverse momentum from 55 to 400 GeV/c. (C) 2017 The Author(s). Published by Elsevier B.V.

A search for massive resonances decaying to a Z boson and a photon is performed in events with a hadronically decaying Z boson candidate, separately in light-quark and b quark decay modes, identified using jet substructure and advanced b tagging techniques. Results are based on samples of proton-proton collisions collected with the CMS detector at the LHC at center-of-mass energies of 8 and 13 TeV, corresponding to integrated luminosities of 19.7 and 2.7 fb(-1), respectively. The results of the search are combined with those of a similar search in the leptonic decay modes of the Z boson, based on the same data sets. Spin-0 resonances with various widths and with masses in a range between 0.2 and 3.0 TeV are considered. No significant excess is observed either in the individual analyses or the combination. The results are presented in terms of upper limits on the production cross section of such resonances and constitute the most stringent limits to date for a wide range of masses. (C) 2017 The Author(s). Published by Elsevier B.V.

A measurement of electroweak-induced production of W gamma and two jets is performed, where the W boson decays leptonically. The data used in the analysis correspond to an integrated luminosity of 19.7 fb(-1) collected by the CMS experiment in root s = 8TeV proton-proton collisions produced at the LHC. Candidate events are selected with exactly one muon or electron, missing transverse momentum, one photon, and two jets with large rapidity separation. An excess over the hypothesis of the standard model without electroweak production of W gamma with two jets is observed with a signi fi cance of 2.7 standard deviations. The cross section measured in the fi ducial region is 10.8 +/- 4.1(stat) +/- 3.4(syst) +/- 0. 3(lumi) fb, which is consistent with the standard model electroweak prediction. The total cross section for W gamma in association with two jets in the same fi ducial region is measured to be 23.2 +/- 4.3(stat) +/- 1.7(syst) +/- 0.6(lumi) fb, which is consistent with the standard model prediction from the combination of electroweakand quantum chromodynamics-induced processes. No deviations are observed from the standard model predictions and experimental limits on anomalous quartic gauge couplings integral M,0- 7 /Lambda(4), integral T,0- 2 /Lambda(4), and integral T,5-7/Lambda(4) are set at 95% con fi dence level.

A search for direct production of top squark pairs in events with jets and large transverse momentum imbalance is presented. The data are based on proton-proton collisions at a center-of-mass energy of 13 TeV, collected with the CMS detector in 2016 at the CERN LHC, and correspond to an integrated luminosity of 35.9 fb(-1). The search considers a variety of R-parity conserving supersymmetric models, including ones for which the top squark and neutralino masses are nearly degenerate. Specialized jet reconstruction tools are developed to exploit the unique characteristics of the signal topologies. With no significant excess of events observed above the standard model expectations, upper limits are set on the direct top squark pair production cross section in the context of simplified supersymmetric models for various decay hypotheses. Models with larger differences in mass between the top squark and neutralino are probed for masses up to 1040 and 500 GeV, respectively, whereas models with a more compressed mass hierarchy are probed up to 660 and 610 GeV, respectively. The smallest mass difference probed is for masses near to 550 and 540 GeV, respectively.

This paper reports the measurement of J/psi meson production in proton proton (pp) and proton lead (pPb) collisions at a center-of-mass energy per nucleon pair of 5.02 TeV by the CMS experiment at the LW. The data samples used in the analysis correspond to integrated luminosities of 28 ph(-1) and 35 nb(-1) for pp and pPb collisions, respectively. Prompt and nonprompt J/psi mesons, the latter produced in the decay of B hadrons, are measured in their dilution decay channels, Differential cross sections are measured in the transverse momentum range of 2 LT p(T) LT 30 GeV/c, and center-of-mass rapidity ranges of vertical bar y(CM)vertical bar LT 2.4 (pp) and -2.87 LT y(CM) LT 1.93 (pPb). The nuclear modification factor, R-pPb, is measured as a function of both p(T) and y(CM). Small modifications to the J/psi cross sections are observed in pPb relative to pp collisions. The ratio of J/psi production cross sections in p-going and Pb-going directions, R-FB, studied as functions of p(T) and y(CM), shows a significant decrease for increasing transverse energy deposited at large pseudorapidities. These results, which cover a wide kinematic range, provide new insight on the role of cold nuclear matter effects on prompt and nonprompt J/psi production.

The first measurement of the jet mass m(jet) of top quark jets produced in t (t) over bar events from pp collisions at root s = 8 TeV is reported for the jet with the largest transverse momentum p(T) in highly boosted hadronic top quark decays. The data sample, collected with the CMS detector, corresponds to an integrated luminosity of 19.7 fb(-1). The measurement is performed in the lepton+jets channel in which the products of the semileptonic decay t - GT bW with W - GT l nu where l is an electron or muon, are used to select t (t) over bar events with large Lorentz boosts. The products of the fully hadronic decay t - GT bW with W - GT q (q) over bar are reconstructed using a single Cambridge-Aachen jet with distance parameter R = 1.2, and pT GT 400 GeV. The t (t) over bar cross section as a function of m(jet) is unfolded at the particle level and is used to test the modelling of highly boosted top quark production. The peak position of the m(jet) distribution is sensitive to the top quark mass m(t), and the data are used to extract a value of m(t) to assess this sensitivity.

A search for the production of a single top quark in association with a Z boson is presented, both to identify the expected standard model process and to search for flavour changing neutral current interactions. The data sample corresponds to an integrated luminosity of 19.7 fb(-1) recorded by the CMS experiment at the LHC in proton-proton collisions at root s = 8 TeV. Final states with three leptons (electrons or muons) and at least one jet are investigated. An events yield compatible with tZq standard model production is observed, and the corresponding cross section is measured to be sigma(pp - GT tZq - GT lvbl(+)l(-) q) = 10(-7)(+8) fb with a significance of 2.4 standard deviations. No presence of flavour-changing neutral current production of tZq is observed. Exclusion limits at 95% confidence level on the branching fractions of a top quark decaying to a Z boson and an up or a charm quark are found to be B(t - GT Zu) LT 0.022% and B(t - GT Zc) LT 0.049%.

Results are presented from a search for the electroweak production of supersymmetric particles in pp collisions in final states with two T leptons. The data sample corresponds to an integrated luminosity between 18.1 fb(-1) and 19.6 fb(-1) depending on the final state of T lepton decays, at root s = 8 TeV, collected by the CMS experiment at the LHC. The observed event yields in the signal regions are consistent with the expected standard model backgrounds. The results are interpreted using simplified models describing the pair production and decays of charginos or T sleptons. For models describing the pair production of the lightest chargino, exclusion regions are obtained in the plane of chargino mass vs. neutralino mass under the following assumptions: the chargino decays into third-generation sleptons, which are taken to be the lightest sleptons, and the sleptons masses lie midway between those of the chargino and the neutralino. Chargino masses below 420 GeV are excluded at a 95% confidence level in the limit of a massless neutralino, and for neutralino masses up to 100 GeV, chargino masses up to 325 GeV are excluded at 95% confidence level. Constraints are also placed on the cross section for pair production of T sleptons as a function of mass, assuming a massless neutralino.

Transverse momentum spectra of charged pions, kaons, and protons are measured in proton-proton collisions at root s = 13 TeV with the CMS detector at the LHC. The particles, identified via their energy loss in the silicon tracker, are measured in the transverse momentum range of p(T) approximate to 0.1-1.7 GeV/c and rapidities vertical bar y vertical bar LT 1. The pT spectra and integrated yields are compared to previous results at smaller ffiffiffi root s and to predictions of Monte Carlo event generators. The average pT increases with particle mass and charged particle multiplicity of the event. Comparisons with previous CMS results at root s = 0.9, 2.76, and 7 TeV show that the average pT and the ratios of hadron yields feature very similar dependences on the particle multiplicity in the event, independently of the center-of-mass energy of the pp collision.

Charge-dependent azimuthal particle correlations with respect to the second-order event plane in p-Pb and PbPb collisions at a nucleon-nucleon center-of-mass energy of 5.02 TeV have been studied with the CMS experiment at the LHC. The measurement is performed with a three-particle correlation technique, using two particles with the same or opposite charge within the pseudorapidity range broken vertical bar eta broken vertical bar LT 2.4, and a third particle measured in the hadron forward calorimeters (4.4 LT broken vertical bar eta broken vertical bar LT 5). The observed differences between the same and opposite sign correlations, as functions of multiplicity and. gap between the two charged particles, are of similar magnitude in p-Pb and PbPb collisions at the same multiplicities. These results pose a challenge for the interpretation of charge-dependent azimuthal correlations in heavy ion collisions in terms of the chiral magnetic effect.

The cross section for the production of single top quarks in the t channel is measured in proton- proton collisions at 13TeV with the CMS detector at the LHC. The analyzed data correspond to an integrated luminosity of 2.2fb(-1). The event selection requires one muon and two jets where one of the jets is identified as originating from a bottom quark. Several kinematic variables are then combined into a multivariate discriminator to distinguish signal from background events. A fit to the distribution of the discriminating variable yields a total cross section of 238 +/- 13 (stat)+/- 29(syst) pband a ratio of top quark and top antiquark production of Rt-ch.= 1.81 +/- 0.18 (stat)+/- 0.15(syst). From the total cross section the absolute value of the CKM matrix element Vtbis calculated to be 1.05 +/- 0.07 (exp)+/- 0.02(theo). All results are in agreement with the standard model predictions. (C) 2017 The Author(s). Published by Elsevier B.V.

The differential cross section for inclusive particle production as a function of energy in proton-proton collisions at a center-of-mass energy of 13 TeV is measured in the very forward region of the CMS detector. The measurement is based on data collected with the CMS apparatus at the LHC, and corresponds to an integrated luminosity of 0.34 mu b(-1). The energy is measured in the CASTOR calorimeter, which covers the pseudorapidity region -6.6 LT eta LT -5.2. The results are given as a function of the total energy deposited in CASTOR, as well as of its electromagnetic and hadronic components. The spectra are sensitive to the modeling of multiparton interactions in pp collisions, and provide new constraints for hadronic interaction models used in collider and in high energy cosmic ray physics.

A search for charged Higgs bosons produced via vector boson fusion and decaying into W and Z bosons using proton-proton collisions at root s = 13 TeV is presented. The data sample corresponds to an integrated luminosity of 15.2 fb(-1) collected with the CMS detector in 2015 and 2016. The event selection requires three leptons (electrons or muons), two jets with large pseudorapidity separation and high dijet mass, and missing transverse momentum. The observation agrees with the standard model prediction. Limits on the vector boson fusion production cross section times branching fraction for new charged physical states are reported as a function of mass from 200 to 2000 GeV and interpreted in the context of Higgs triplet models.

A measurement is presented of the triple-differential dijet cross section at a centre-of-mass energy of 8 TeV using 19.7 fb(-1) of data collected with the CMS detector in proton-proton collisions at the LHC. The cross section is measured as a function of the average transverse momentum, half the rapidity separation, and the boost of the two leading jets in the event. The cross section is corrected for detector effects and compared to calculations in perturbative quantum chromodynamics at next-to-leading order accuracy, complemented with electroweak and nonperturbative corrections. New constraints on parton distribution functions are obtained and the inferred value of the strong coupling constant is alpha(S)(M-Z) = 0.1199 +/- 0.0015 (exp)(-0.0020)(+0.0031) (theo), where M-Z is the mass of the Z boson.