Results on two-particle angular correlations for charged particles emitted in pPb collisions at a nucleon-nucleon center-of-mass energy of 5.02 TeV are presented. The analysis uses two million collisions collected with the CMS detector at the LHC. The correlations are studied over a broad range of pseudorapidity, eta, and full azimuth, phi, as a function of charged particle multiplicity and particle transverse momentum, p(T). In high-multiplicity events, a long-range (2 < vertical bar Delta eta vertical bar < 4), near-side (Delta phi approximate to 0) structure emerges in the two-particle Delta eta-Delta phi correlation functions. This is the first observation of such correlations in proton-nucleus collisions, resembling the ridge-like correlations seen in high-multiplicity pp collisions at root s = 7 TeV and in AA collisions over a broad range of center-of-mass energies. The correlation strength exhibits a pronounced maximum in the range of p(T) = 1-1.5 GeV/c and an approximately linear increase with charged particle multiplicity for high-multiplicity events. These observations are qualitatively similar to those in pp collisions when selecting the same observed particle multiplicity, while the overall strength of the correlations is significantly larger in pPb collisions.BMWF ; FWF ; FNRS ; FWO ; CNPq ; CAPES ; FAPERJ ; FAPESP ; MES ; CERN ; CAS ; MoST ; NSFC ; COLCIENCIAS ; MSES ; RPF ; MoER ; ERDF ; Academy of Finland ; MEC ; HIP ; CEA ; CNRS ; BMBF ; DFG ; HGF ; GSRT ; OTKA ; NKTH ; DAE ; DST ; IPM ; SFI ; INFN ; NRF ; WCU ; LAS ; CINVESTAV ; CONACYT ; UASLP-FAI ; MSI ; PAEC ; MSHE ; NSC ; FCT ; JINR ; MON ; RosAtom ; RAS ; RFBR ; MESTD ; SEIDI ; CPAN ; Swiss Funding Agencies ; NSC ; ThEPCenter ; IPST ; STAR ; NSTDA ; TUBITAK ; TAEK ; NASU ; STFC ; DOE ; NSF

Measurements of two- and four-particle angular correlations for charged particles emitted in pPb collisions are presented over a wide range in pseudorapidity and full azimuth. The data, corresponding to an integrated luminosity of approximately 31 nb−1, were collected during the 2013 LHC pPb run at a nucleon–nucleon center-of-mass energy of 5.02 TeV by the CMS experiment. The results are compared to 2.76 TeV semi-peripheral PbPb collision data, collected during the 2011 PbPb run, covering a similar range of particle multiplicities. The observed correlations are characterized by the near-side (|Δϕ|≈0) associated pair yields and the azimuthal anisotropy Fourier harmonics (vn). The second-order (v2) and third-order (v3) anisotropy harmonics are extracted using the two-particle azimuthal correlation technique. A four-particle correlation method is also applied to obtain the value of v2 and further explore the multi-particle nature of the correlations. Both associated pair yields and anisotropy harmonics are studied as a function of particle multiplicity and transverse momentum. The associated pair yields, the four-particle v2, and the v3 become apparent at about the same multiplicity. A remarkable similarity in the v3 signal as a function of multiplicity is observed between the pPb and PbPb systems. Predictions based on the color glass condensate and hydrodynamic models are compared to the experimental resultsThe Austrian Federal Ministry of Science and Research and the Austrian Science Fund ; the Belgian Fonds de la Recherche Scientifique, and Fonds voor Wetenschappelijk Onderzoek ; the Brazilian Funding Agencies ; the Bulgarian Ministry of Education and Science; CERN ; the Chinese Academy of Sciences, Ministry of Science and Technology, and National Natural Science Foundation of China ; the Colombian Funding Agency ; the Croatian Ministry of Science, Education and Sport ; the Research Promotion Foundation, Cyprus; the Ministry of Education and Research ; and European Regional Development Fund, Estonia; the Academy of Finland, Finnish Ministry of Education and Culture, and Helsinki Institute of Physics; the Institut National de Physique Nucleaire et de Physique des Particules/CNRS, and Commissariat a l’Energie Atomique et aux Energies Alternatives/CEA, France; the Bundesministerium fur Bildung und Forschung, Deutsche Forschungsgemeinschaft, and Helmholtz-Gemeinschaft Deutscher Forschungszentren, Germany; the General Secretariat for Research and Technology, Greece; the National Scientific Research Foundation, and National Office for Research and Technology, Hungary; the Department of Atomic Energy and the Department of Science and Technology, India; the Institute for Studies in Theoretical Physics and Mathematics, Iran; the Science Foundation, Ireland; the Istituto Nazionale di Fisica Nucleare, Italy; the Korean Ministry of Education, Science and Technology and the World Class University program of NRF, Republic of Korea; the Lithuanian Academy of Sciences; the Mexican Funding Agencies ; the Ministry of Business, Innovation and Employment, New Zealand; the Pakistan Atomic Energy Commission; the Ministry of Science and Higher Education and the National Science Centre, Poland; the Fundac¸ao para a Ciencia e a Tecnologia, Portugal; JINR, Dubna; the Ministry of Education and Science of the Russian Federation, the Federal Agency of Atomic Energy of the Russian Federation, Russian Academy of Sciences, and the Russian Foundation for Basic Research; the Ministry of Education, Science and Technological Development of Serbia; the Secretaria de Estado de Investigacio´n, Desarrollo e Innovacion and Programa Consolider-Ingenio 2010, Spain; the Swiss Funding Agencies ; the National Science Council, Taipei; the Thailand Center of Excellence in Physics, the Institute for the Promotion of Teaching Science and Technology of Thailand, Special Task Force for Activating Research and the National Science and Technology Development Agency of Thailand ; the Scientific and Technical Research Council of Turkey and Turkish Atomic Energy Authority ; the Science and Technology Facilities Council UK; the U.S. Department of Energy and the U.S. National Science Foundation ; European Union ; the Leventis Foundation ; the A. P. Sloan Foundation ; the Alexander von Humboldt Foundation ; the Belgian Federal Science Policy Office ; the Fonds pour la Formation a` la Recherche dans l’Industrie et dans l’Agriculture (FRIA-Belgium); the Agentschap voor Innovatie door Wetenschap en Technologie (IWTBelgium); the Ministry of Education Youth and Sports (MEYS) of Czech Republic; the Council of Science and Industrial Research India; the Compagnia di San Paolo (Torino); the HOMING PLUS program of Foundation for Polish Science cofinanced by EU Regional Development Fund; and the Thalis and Aristeia programs cofinanced by EU-ESF and the Greek NSRF.

The anisotropy of the azimuthal distributions of charged particles produced in $\sqrt{s_{NN}}=2.76$ TeV PbPb collisions is studied with the CMS experiment at the LHC. The elliptic anisotropy parameter, $v_2$, defined as the second coefficient in a Fourier expansion of the particle invariant yields, is extracted using the event-plane method, two- and four-particle cumulants, and Lee-Yang zeros. The anisotropy is presented as a function of transverse momentum ($p_{\mathrm{T}}$), pseudorapidity ($\eta$) over a broad kinematic range, $0.3<p_{\mathrm{T}}<20$ GeV/c, $\left|\eta \right|<2.4$, and in 12 classes of collision centrality from 0 to $80\%$. The results are compared to those obtained at lower center-of-mass energies, and various scaling behaviors are examined. When scaled by the geometric eccentricity of the collision zone, the elliptic anisotropy is found to obey a universal scaling with the transverse particle density for different collision systems and center-of-mass energies.

This paper presents a search for the pair production of top squarks in events with a single isolated electron or muon, jets, large missing transverse momentum, and large transverse mass. The data...

Results are presented from a search for the rare decays $B_s^0\to {\mu }^{+}{\mu }^{-}$ and $B^0\to {\mu }^{+}{\mu }^{-}$ in $pp$ collisions at $\sqrt{s}=7$ and 8 TeV, with data samples corresponding to integrated luminosities of 5 and $20{\mathrm{fb}}^{-1}$, respectively, collected by the CMS experiment at the LHC. An unbinned maximum-likelihood fit to the dimuon invariant mass distribution gives a branching fraction $\mathcal{B}(B_s^0\to {\mu }^{+}{\mu }^{-})=({3.0}_{-0.9}^{+1.0})\times {10}^{-9}$, where the uncertainty includes both statistical and systematic contributions. An excess of $B_s^0\to {\mu }^{+}{\mu }^{-}$ events with respect to background is observed with a significance of 4.3 standard deviations. For the decay $B^0\to {\mu }^{+}{\mu }^{-}$ an upper limit of $\mathcal{B}(B^0\to {\mu }^{+}{\mu }^{-})<1.1\times {10}^{-9}$ at the 95% confidence level is determined. Both results are in agreement with the expectations from the standard model.