Download or read book Search for the Standard Model Higgs Boson Decaying Into Two Photons in Pp Collisions at Sqrt s written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A search for a Higgs boson decaying into two photons is described. The analysis is performed using a dataset recorded by the CMS experiment at the LHC from pp collisions at a centre-of-mass energy of 7 TeV, which corresponds to an integrated luminosity of 4.8 inverse femtobarns. Limits are set on the cross section of the standard model Higgs boson decaying to two photons. The expected exclusion limit at 95% confidence level is between 1.4 and 2.4 times the standard model cross section in the mass range between 110 and 150 GeV. The analysis of the data excludes, at 95% confidence level, the standard model Higgs boson decaying into two photons in the mass range 128 to 132 GeV. The largest excess of events above the expected standard model background is observed for a Higgs boson mass hypothesis of 124 GeV with a local significance of 3.1 sigma. The global significance of observing an excess with a local significance greater than 3.1 sigma anywhere in the search range 110-150 GeV is estimated to be 1.8 sigma. More data are required to ascertain the origin of this excess.
Download or read book Search for the Standard Model Higgs Boson in the Diphoton Final State in p bar p Collisions at sqrt s written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a search for the Standard Model Higgs boson decaying into a pair of photons produced in p$p\bar{p}$ collisions with a center of mass energy of 1.96 TeV. The results are based on data corresponding to an integrated luminosity of 10 fb-1 collected by the CDF II detector. Higgs boson candidate events are identified by reconstructing two photons in either the central or plug regions of the detector. The acceptance for identifying photons is significantly increased by using a new algorithm designed to reconstruct photons in the central region that have converted to an electron-positron pair. In addition, a new neural network discriminant is employed to improve the identification of non-converting central photons. No evidence for the Higgs boson is observed in the data, and we set an upper limit on the cross section for Higgs boson production multiplied by the H 2![gamma][gamma] branching ratio. For a Higgs boson mass of 125 GeV/c 2, we obtain an observed (expected) limit of 12.2 (10.8) times the Standard Model prediction at the 95% credibility level.
Download or read book Search for a Higgs Boson Decaying Into gamma gamma to ell ell gamma with Low Dilepton Mass in Pp Collisions at sqrt s written by and published by . This book was released on 2015 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: Our search is described for a Higgs boson decaying into two photons, one of which has an internal conversion to a muon or an electron pair (ll?). The analysis is performed using proton–proton collision data recorded 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. The events selected have an opposite-sign muon or electron pair and a high transverse momentum photon. No excess above background has been found in the three-body invariant mass range 120 mll? 150 GeV, and limits have been derived for the Higgs boson production cross section times branching fraction for the decay H → ?*? → ll?, where the dilepton invariant mass is less than 20 GeV. A Higgs boson with mH=125 GeV has a 95% confidence level (CL) exclusion observed (expected) limit is 6.7 (5.9sup+2.8/supsub-1.8/sub ) times the standard model prediction. Additionally, an upper limit at 95% CL on the branching fraction of H → (J/?)? for the 125 GeV Higgs boson is set at 1.5 × 10
Download or read book Search for a Higgs Boson in the Decay Channel H to ZZ to q Qbar ell L in pp Collisions at sqrt s written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A search for the standard model Higgs boson decaying into two Z bosons with subsequent decay into a final state containing two quark jets and two leptons, H to ZZ(*) to q q-bar l-l+ is presented. Results are based on data corresponding to an integrated luminosity of 4.6 inverse femtobarns of proton-proton collisions at sqrt(s)=7 TeV, collected with the CMS detector at the LHC. In order to discriminate between signal and background events, kinematic and topological quantities, including the angular spin correlations of the decay products, are employed. Events are further classified according to the probability of the jets to originate from quarks of light or heavy flavor or from gluons. No evidence for the Higgs boson is found, and upper limits on its production cross section are determined for a Higgs boson of mass between 130 and 600 GeV.
Download or read book Search for the Standard Model Higgs Boson Decaying to a W Pair in the Fully Leptonic Final State in pp Collisions at sqrt s written by and published by . This book was released on 2012 with total page 113 pages. Available in PDF, EPUB and Kindle. Book excerpt: A search for the standard model Higgs boson decaying to W+W- in pp collisions at sqrt(s) = 7 TeV is reported. The data are collected at the LHC with the CMS detector, and correspond to an integrated luminosity of 4.6 inverse femtobarns. The W+W- candidates are selected in events with two charged leptons and large missing transverse energy. No significant excess of events above the standard model background expectations is observed, and upper limits on the Higgs boson production relative to the standard model Higgs expectation are derived. The standard model Higgs boson is excluded in the mass range 129-270 GeV at 95% confidence level.
Download or read book Search for a Higgs Boson Decaying Into gamma gamma to ell ell gamma with Low Dilepton Mass in Pp Collisions at sqrt s written by and published by . This book was released on 2015 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: Our search is described for a Higgs boson decaying into two photons, one of which has an internal conversion to a muon or an electron pair (ll[gamma]). The analysis is performed using proton-proton collision data recorded 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. The events selected have an opposite-sign muon or electron pair and a high transverse momentum photon. No excess above background has been found in the three-body invariant mass range 120
Download or read book Search for a Higgs like Boson Decaying to Two Photons in p bar p Collisions at sqrt s written by and published by . This book was released on 2013 with total page 149 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a search for the Standard Model (SM) Higgs boson decaying to two photons using the 9.6 fb-1 of p$\bar{p}$ collisions at √s = 1.96 TeV collected by the D0 detector at the Tevatron from July 2002 to September 2011. The data corresponds to the complete data-set in the RunII period of the Tevatron. This thesis employs a multivariate technique, boosted decision trees, to optimize the discrimination of signal from background. No significant excess of data above theoretical prediction is observed, so limits on the ratio of the production cross section times the branching ratio to the SM value are set at 95% confidence level as a function of hypothetical Higgs boson mass. The expected and observed limits on this ratio are 8.7 and 12.8 respectively at 125 GeV. We also interpret the data in the fermiophobic Higgs model. The result has reached a sensitivity of 114 GeV, and we set a lower limit on the fermiophobic Higgs mass of MHf > 113 GeV.
Download or read book Combined Results of Searches for the Standard Model Higgs Boson in Pp Collisions at Sqrt s written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Combined results are reported from searches for the standard model Higgs boson in proton-proton collisions at sqrt(s)=7 TeV in five Higgs boson decay modes: gamma pair, b-quark pair, tau lepton pair, W pair, and Z pair. The explored Higgs boson mass range is 110-600 GeV. The analysed data correspond to an integrated luminosity of 4.6-4.8 inverse femtobarns. The expected excluded mass range in the absence of the standard model Higgs boson is 118-543 GeV at 95% CL. The observed results exclude the standard model Higgs boson in the mass range 127-600 GeV at 95% CL, and in the mass range 129-525 GeV at 99% CL. An excess of events above the expected standard model background is observed at the low end of the explored mass range making the observed limits weaker than expected in the absence of a signal. The largest excess, with a local significance of 3.1 sigma, is observed for a Higgs boson mass hypothesis of 124 GeV. The global significance of observing an excess with a local significance greater than 3.1 sigma anywhere in the search range 110-600 (110-145) GeV is estimated to be 1.5 sigma (2.1 sigma). More data are required to ascertain the origin of this excess.
Download or read book Search for a Higgs Boson Decaying Into a Z and a Photon in Pp Collisions at sqrt s written by and published by . This book was released on 2013 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Quest For The Origin Of Particles And The Universe Proceedings Of The Kmi Inauguration Conference written by Yasumichi Aoki and published by World Scientific. This book was released on 2013-03-25 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Kobayashi-Maskawa Institute for the Origin of Particles and the Universe (KMI) was founded at Nagoya University in 2010 under the directorship of T Maskawa, in celebration of the 2008 Nobel Prize in Physics for M Kobayashi and T Maskawa, both who are alumni of Nagoya University. In commemoration of the new KMI building in 2011, the KMI Inauguration Conference (KMIIN) was organized to discuss perspectives of various fields — both theoretical and experimental studies of particle physics and astrophysics — as the main objectives of the KMI activity.This proceedings contains a welcome address by T Maskawa conveying his hopes for KMI to create new revolutionary directions in the spirit of Shoichi Sakata, a great mentor of both Maskawa and Kobayashi. Invited speakers, world-leading scientists in the fields, and the young scientists at KMI contributed to this volume containing theoretical studies of strongly coupled gauge theories in view of LHC phenomenology, string theory approach and lattice studies as well as hot/dense QCD system, and also super-symmetric GUT models, etc., together with experimental studies of LHC physics, B physics, neutrino physics and the related astrophysics and cosmology. The volume yields a unique synergy of particle physics and astrophysics, closely related to the main activity of KMI encompassing particle theory (including lattice computer simulations), particle physics experiments, cosmology, and astrophysics observations.
Download or read book Search for the Standard Model Higgs Boson in the Decay Channel H to Z Z to 4 Leptons in pp Collisions at sqrt s written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A search for a Higgs boson in the four-lepton decay channel H to ZZ, with each Z boson decaying to an electron or muon pair, is reported. The search covers Higgs boson mass hypotheses in the range 110 mH
Download or read book Search for a Standard Model Higgs Boson Decaying to Two Photons in CMS at the LHC written by Yong Yang and published by . This book was released on 2013 with total page 652 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Searching For New Physics At Small And Large Scales Tasi 2012 Proceedings Of The 2012 Theoretical Advanced Study Institute In Elementary Particle Physics written by Martin Schmaltz and published by World Scientific. This book was released on 2013-08-28 with total page 521 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume is a compilation of the lectures at TASI 2012, held in Boulder, Colorado, June 2012. The program comprises two parallel lecture series on particle physics and on cosmology. The particle physics lectures covers LHC related experimental techniques, phenomenology, as well as basics in physics beyond the standard model. The cosmology series give a general introduction to modern cosmology with special attention to the topics of dark matter, the microwave background and alternatives to the standard model of cosmology. The lectures are accessible to graduate students at the initial stages of their research careers.
Download or read book Search for Decays of the Higgs Boson Into Muons in P P Collisions with the CMS Detector written by Luisa Fernanda Chaparro Sierra and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "In this thesis a search for events in which the recently discovered Higgs boson decays into a pair of muons is presented. The search was performed using the data collected by the CMS experiment at CERN during Run 2 of the LHC accelerator. The data comes from p-p collisions at (sqrt) s = 13 TeV, corresponding to an integrated luminosity of 35.9 fb^-1 . In the Standard Model of Particles and Fields (SM) once the mass of the Higgs boson is known, all its couplings get fixed, including the coupling to muons. Any significant deviations in the experimental results from the values expected from the SM predictions could indicate the onset of new physics. Therefore, it is very important to measure all possible decay channel parameters. The H to (mu) ^+ (mu)^- is the only channel where the Higgs boson couples to the second generation of fermions that could be measured during Run 2 of the LHC. The Higgs coupling to fermions is proportional to the mass of the particles, and since the muons are very light, any measurement in this channel provides valuable information about the Higgs Yukawa coupling to fermions. The small branching ratio of the H to (mu) ^+ (mu)^- decay (2.4 * 10^-4 ) indicates that with the statistics collected by CMS during the Run 2 of the LHC, the expected number of events is also small. Therefore, any improvement in the event selection should be included in the analysis. In this thesis I have focused in recovering events in which the final-state muons might have radiated photons (final-state radiation, FSR) and in correcting the resulting invariant mass distribution. Two techniques were implemented: a cut-based analysis and a multivariate analysis. A study of the impact of the FSR photon recovery in the Higgs mass reconstruction is presented. These studies were done as part of the research activities of the CMS H2Mu Analysis Group."--Tomado del Formato de Documento de Grado.
Download or read book Search for a Very Light NMSSM Higgs Boson Produced in Decays of the 125 GeV Scalar Boson and Decaying Into tau Leptons in Pp Collisions at sqrt s written by and published by . This book was released on 2015 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: Our search for a very light Higgs boson decaying into a pair of t leptons is presented within the framework of the next-to-minimal supersymmetric standard model. This search is based on a data set corresponding to an integrated luminosity of 19.7 fb-1 of proton-proton collisions collected by the CMS experiment at a centre-of-mass energy of 8 TeV. The signal is defined by the production of either of the two lightest scalars, h1 or h2, via gluon-gluon fusion and subsequent decay into a pair of the lightest Higgs bosons, a1 or h1. The h1 or h2 boson is identified with the observed state at a mass of 125 GeV. The analysis searches for decays of the a1 (h1) states into pairs of t leptons and covers a mass range for the a1 (h1) boson of 4 to 8 GeV. Furthermore, the search reveals no significant excess in data above standard model background expectations, and an upper limit is set on the signal production cross section times branching fraction as a function of the a1 (h1) boson mass. The 95% confidence level limit ranges from 4.5 pb at ma1 (mh1) = 8 GeV to 10.3 pb at ma1 (mh1) = 5 GeV.
Download or read book Inclusive b Jet Production in Proton Proton Collisions written by Patrick L.S. Connor and published by Springer Nature. This book was released on 2019-11-29 with total page 325 pages. Available in PDF, EPUB and Kindle. Book excerpt: ^ 74 GeV and |y| 2.4; the b jets must contain a B hadron. The measurement has significant statistics up to p T ∼ O(TeV). Advanced methods of unfolding are performed to extract the signal. It is found that fixed-order calculations with underlying event describe the measurement well.
Download or read book Search for Two Higgs Bosons in Final States Containing Two Photons and Two Bottom Quarks written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A search is presented for the production of two Higgs bosons in final states containing two photons and two bottom quarks. Both resonant and nonresonant hypotheses are investigated. The analyzed data correspond to an integrated luminosity of 19.7 inverse femtobarns of proton-proton collisions at sqrt(s) = 8 TeV collected with the CMS detector. Good agreement is observed between data and predictions of the standard model (SM). Upper limits are set at 95% confidence level on the production cross section of new particles and compared to the prediction for the existence of a warped extra dimension. When the decay to two Higgs bosons is kinematically allowed, assuming a mass scale LambdaR = 1 TeV for the model, the data exclude a radion scalar at masses below 980 GeV. The first Kaluza-Klein excitation mode of the graviton in Randall-Sundrum models is excluded for masses between 325 and 450 GeV. Limits set on nonresonant production constrain the parameter space for anomalous Higgs boson couplings.
