Properties of the Higgs boson with mass near 125 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 , , , , , and pairs. The data samples were collected in 2011 and 2012 and correspond to integrated luminosities of up to 5.1 at 7 and up to 19.7 at 8. From the high-resolution and channels, the mass of the Higgs boson is determined to be . 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 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.

Observation of the diphoton decay mode of the recently discovered Higgs boson and measurement of some of its properties are reported. The analysis uses the entire dataset collected by the CMS experiment in proton-proton collisions during the 2011 and 2012 LHC running periods. The data samples correspond to integrated luminosities of 5.1at and 19.7at 8 . A clear signal is observed in the diphoton channel at a mass close to 125 with a local significance of , where a significance of is expected for the standard model Higgs boson. The mass is measured to be , and the best-fit signal strength relative to the standard model prediction is . Additional measurements include the signal strength modifiers associated with different production mechanisms, and hypothesis tests between spin-0 and spin-2 models.

The second-order azimuthal anisotropy Fourier harmonics, v 2 , are obtained in p-Pb and PbPb collisions over a wide pseudorapidity (η) range based on correlations among six or more charged particles. The p-Pb data, corresponding to an integrated luminosity of 35 nb −1 , were collected during the 2013 LHC p-Pb run at a nucleon-nucleon center-of-mass energy of 5.02 TeV by the CMS experiment. A sample of semiperipheral PbPb collision data at ffiffiffiffiffiffiffi ffi s NN p ¼ 2.76 TeV, corresponding to an integrated luminosity of 2.5 μb −1 and covering a similar range of particle multiplicities as the p-Pb data, is also analyzed for comparison. The six-and eight-particle cumulant and the Lee-Yang zeros methods are used to extract the v 2 coefficients, extending previous studies of two-and four-particle correlations. For both the p-Pb and PbPb systems, the v 2 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 Δη) correlations in both systems. The ratios of v 2 values corresponding to correlations including different numbers of particles are compared to theoretical predictions that assume a hydrodynamic behavior of a p-Pb system dominated by fluctuations in the positions of participant nucleons. These results provide new insights into the multiparticle dynamics of collision systems with a very small overlapping region. DOI: 10.1103/PhysRevLett.115.012301 PACS numbers: 25.75.Gz Measurements at the CERN LHC have led to the discovery of two-particle azimuthal correlation structures at large relative pseudorapidity (long range) in protonproton (pp) [1] and proton-lead (p-Pb) [2][3][4][5] collisions. Similar long-range structure has also been observed for ffiffiffiffiffiffiffi ffi [6,7]. The results extend previous studies of relativistic heavy-ion collisions, such as for the copper-copper [8], gold-gold [8][9][10][11][12], and lead-lead (PbPb) [13][14][15][16][17][18] systems, where similar long-range, two-particle correlations at small relative azimuthal angle jΔϕj ≈ 0 were first observed. A fundamental question is whether the observed behavior results from correlations exclusively between particle pairs, or if it is a multiparticle, collective effect. It has been suggested that the hydrodynamic collective flow of a strongly interacting and expanding medium [19][20][21] is responsible for these long-range correlations in central and midcentral heavy-ion collisions. The origin of the observed long-range correlations in collision systems with a small overlapping region, such as for pp and p-Pb collisions, is not clear since for these systems the formation of an extended hot medium is not necessarily expected. Various theoretical models have been proposed to interpret the pp [22,23] and p-Pb results, including initial-state gluon saturation without any final state interactions [24,25] and, similar to what is thought to occur in heavi...

Measurements are presented of the t-channel single-top-quark production cross section in proton-proton collisions at √ s = 8 TeV. The results are based on a data sample corresponding to an integrated luminosity of 19.7 fb −1 recorded with the CMS detector at the LHC. The cross section is measured inclusively, as well as separately for top (t) and antitop (t), in final states with a muon or an electron. The measured inclusive tchannel cross section is σ t-ch. = 83.6 ± 2.3 (stat.) ± 7.4 (syst.) pb. The single t and t cross sections are measured to be σ t-ch. (t) = 53.8 ± 1.5 (stat.) ± 4.4 (syst.) pb and σ t-ch. (t) = 27.6 ± 1.3 (stat.) ± 3.7 (syst.) pb, respectively. The measured ratio of cross sections is R t-ch. = σ t-ch. (t)/σ t-ch. (t) = 1.95±0.10 (stat.)±0.19 (syst.), in agreement with the standard model prediction. The modulus of the Cabibbo-Kobayashi-Maskawa matrix element V tb is extracted and, in combination with a previous CMS result at √ s = 7 TeV, a value |V tb | = 0.998 ± 0.038 (exp.) ± 0.016 (theo.) is obtained.

The observation of a new b baryon via its strong decay into Ä À b þ (plus charge conjugates) is reported. The measurement uses a data sample of pp collisions at ffiffi ffi s p ¼ 7 TeV collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 5:3 fb À1 . The known Ä À b baryon is reconstructed via the decay chain Ä À b ! J=c Ä À ! þ À à 0 À , with à 0 ! p À . A peak is observed in the distribution of the difference between the mass of the Ä À b þ system and the sum of the masses of the Ä À b and þ , with a significance exceeding 5 standard deviations. The mass difference of the peak is 14:84 AE 0:74ðstatÞ AE 0:28ðsystÞ MeV. The new state most likely corresponds to the J P ¼ 3=2 þ companion of the Ä b . DOI: 10.1103/PhysRevLett.108.252002 PACS numbers: 14.20.Mr According to the well-established quark model and corresponding spectroscopy of baryons, there are several predicted baryons containing one strange and one beauty valence quark. These include the Ä b (ground state) and Ä 0 b , both with total angular momentum and parity J P ¼ 1=2 þ , a J P ¼ 3=2 þ state with angular momentum L ¼ 0 (often referred to, as will be done in this Letter, as Ä Ã b ), and two states with J P ¼ 1=2 À and 3=2 À , both with angular momentum L ¼ 1. These baryons can be neutral (valence quark content u À s À b) or negatively charged (d À s À b). At the Tevatron, baryons with masses and decay modes consistent with the theoretical predictions for the ground state Ä b baryons have been observed [1][2][3], although their quantum numbers have not yet been established. The allowed decays of the experimentally missing Ä b states should be analogous to the charmed sector [4][5][6]. In addition, theoretical calculations [7][8][9][10][11] predict the mass difference between the Ä 0 b and Ä b to be smaller than the mass of the pion, in which case the strong decay Ä 0 b ! Ä b is kinematically forbidden. The mass difference between the Ä Ã b and Ä b , however, is expected to be large enough to allow such a decay.This Letter presents a search for the decay . The CMS apparatus is described in detail in Ref. [12]. Its central feature is a superconducting solenoid, of 6 m internal diameter, providing a field of 3.8 T. The main subdetectors used in this analysis are the silicon tracker and the muon systems. The silicon tracker, composed of pixel and strip detector modules, is immersed in the magnetic field, and enables the measurement of charged particle momenta over the pseudorapidity range jj < 2:5, where ¼ À lnðtan=2Þ and is the polar angle of the track relative to the counterclockwise beam direction. Muons are identified in the range jj < 2:4 using gas-ionization detectors embedded in the steel return yoke of the magnet.The events used in this analysis were collected using the two-level trigger system of CMS. The first level consists of custom hardware processors and uses information from the muon systems to select events with two muons. The ''highlevel trigger'' processor farm further decreases the event rate befor...