Tania Moulik

Search for stopped gluinos from pp collisions at √{s)=1.96 TeV

Long-lived, heavy particles are predicted in a number of models beyond the standard model of particle physics. We present the first direct search for such particles decays, occurring up to 100 h after their production and not synchronized with an accelerator bunch crossing. We apply the analysis to the gluino (g), predicted in split supersymmetry, which after hadronization can become charged and lose enough momentum through ionization to come to rest in dense particle detectors. Approximately 410 pb(-1) of pp collisions at square root(s) = 1.96 TeV collected with the D0 detector during Run II of the Fermilab Tevatron collider are analyzed in search of such stopped gluinos decaying into a gluon and a neutralino (chi(1)(0)). Limits are placed on the (gluino cross section) x (probability to stop) x [BR(g --> g chi(1)(0))] as a function of the gluino and chi(1)(0) masses, for gluino lifetimes from 30 micros-100 h.

Measurement of the B(0)(s) Lifetime Using Semileptonic Decays

We report a measurement of the Bs(0) lifetime in the semileptonic decay channel Bs(0) --> Ds- mu+ nuX (and its charge conjugate), using approximately 0.4 fb(-1) of data collected with the D0 detector during 2002-2004. Using 5176 reconstructed Ds- mu+ signal events, we have measured the Bs(0) lifetime to be tau(Bs(0))=1.398+/-0.044(stat)(-0.025)(+0.028)(syst) ps. This is the most precise measurement of the Bs(0) lifetime to date.

Search for Resonant Pair Production of Neutral Long-Lived Particles Decaying to bb in pp Collisions at √ s = 1.96 TeV

We report on a first search for resonant pair production of neutral long-lived particles (NLLP) which each decay to a bb pair, using 3.6 fb(-1) of data recorded with the D0 detector at the Fermilab Tevatron collider. We search for pairs of displaced vertices in the tracking detector at radii in the range 1.6-20 cm from the beam axis. No significant excess is observed above background, and upper limits are set on the production rate in a hidden-valley benchmark model for a range of Higgs boson masses and NLLP masses and lifetimes.

Search for Neutral Higgs Bosons at High tanβ in the b(h/H/A)→bτ(+)τ(−) Channel

The first search in pp collisions at √s = 1.96 TeV for the production of neutral Higgs bosons in association with bottom quarks and decaying in two tau leptons is presented. The cross section for this process is enhanced in many extensions of the standard model, such as its minimal supersymmetric extension (MSSM) at large tanβ. The data, corresponding to an integrated luminosity of 328 pb -1 , were collected with the DO detector at the Fermilab Tevatron Collider. An upper limit is set on the production cross section of neutral Higgs bosons in the mass range of 90 to 150 GeV, and this limit is used to exclude part of the MSSM parameter space.

Search for the rare decay B(0)(s)→μ(+)μ(−)

V.M. Abazov ai, B. Abbott bu, M. Abolins bj, B.S. Acharya ac, M. Adams av, T. Adams at, G.D. Alexeev ai, G. Alkhazov am, A. Alton bi,1, G. Alverson bh, G.A. Alves b, L.S. Ancu ah, M. Aoki au, Y. Arnoud n, M. Arov be, A. Askew at, B. Åsman an, O. Atramentov bm, C. Avila h, J. BackusMayes cb, F. Badaud m, L. Bagby au, B. Baldin au, D.V. Bandurin at, S. Banerjee ac, E. Barberis bh, A.-F. Barfuss o, P. Baringer bc, J. Barreto b, J.F. Bartlett au, U. Bassler r, S. Beale f, A. Bean bc, M. Begalli c, M. Begel bs, C. Belanger-Champagne an, L. Bellantoni au, J.A. Benitez bj, S.B. Beri aa, G. Bernardi q, R. Bernhard v, I. Bertram ao, M. Besançon r, R. Beuselinck ap, V.A. Bezzubov al, P.C. Bhat au, V. Bhatnagar aa, G. Blazey aw, S. Blessing at, K. Bloom bl, A. Boehnlein au, D. Boline br, T.A. Bolton bd, E.E. Boos ak, G. Borissov ao, T. Bose bg, A. Brandt bx, O. Brandt w, R. Brock bj, G. Brooijmans bp, A. Bross au, D. Brown s, X.B. Bu g, D. Buchholz ax, M. Buehler ca, V. Buescher x, V. Bunichev ak, S. Burdin ao,2, T.H. Burnett cb, C.P. Buszello ap, P. Calfayan y, B. Calpas o, S. Calvet p, E. Camacho-Pérez af, J. Cammin bq, M.A. Carrasco-Lizarraga af, E. Carrera at, B.C.K. Casey au, H. Castilla-Valdez af, S. Chakrabarti br, D. Chakraborty aw, K.M. Chan ba, A. Chandra bz, G. Chen bc, S. Chevalier-Théry r, D.K. Cho bw, S.W. Cho ae, S. Choi ae, B. Choudhary ab, T. Christoudias ap, S. Cihangir au, D. Claes bl, J. Clutter bc, M. Cooke au, W.E. Cooper au, M. Corcoran bz, F. Couderc r, M.-C. Cousinou o, A. Croc r, D. Cutts bw, M. Ćwiok ad, A. Das ar, G. Davies ap, K. De bx, S.J. de Jong ah, E. De La Cruz-Burelo af, F. Déliot r, M. Demarteau au, R. Demina bq, D. Denisov au, S.P. Denisov al, S. Desai au, K. DeVaughan bl, H.T. Diehl au, M. Diesburg au, A. Dominguez bl, T. Dorland cb, A. Dubey ab, L.V. Dudko ak, D. Duggan bm, A. Duperrin o, S. Dutt aa, A. Dyshkant aw, M. Eads bl, D. Edmunds bj, J. Ellison as, V.D. Elvira au, Y. Enari q, S. Eno bf, H. Evans ay, A. Evdokimov bs, V.N. Evdokimov al, G. Facini bh, A.V. Ferapontov bw, T. Ferbel bf,bq, F. Fiedler x, F. Filthaut ah, W. Fisher bj, H.E. Fisk au, M. Fortner aw, H. Fox ao, S. Fuess au, T. Gadfort bs, A. Garcia-Bellido bq, V. Gavrilov aj, P. Gay m, W. Geist s, W. Geng o,bj, D. Gerbaudo bn, C.E. Gerber av, Y. Gershtein bm, D. Gillberg f, G. Ginther au,bq, G. Golovanov ai, A. Goussiou cb, P.D. Grannis br, S. Greder s, H. Greenlee au, Z.D. Greenwood be, E.M. Gregores d, G. Grenier t, Ph. Gris m, J.-F. Grivaz p, A. Grohsjean r, S. Grünendahl au, M.W. Grünewald ad, F. Guo br, J. Guo br, G. Gutierrez au, P. Gutierrez bu, A. Haas bp,3, P. Haefner y, S. Hagopian at, J. Haley bh, L. Han g, K. Harder aq, A. Harel bq, J.M. Hauptman bb, J. Hays ap, T. Hebbeker u, D. Hedin aw, A.P. Heinson as, U. Heintz bw, C. Hensel w, I. Heredia-De La Cruz af, K. Herner bi, G. Hesketh bh, M.D. Hildreth ba, R. Hirosky ca, T. Hoang at, J.D. Hobbs br, B. Hoeneisen l, M. Hohlfeld x, S. Hossain bu, Y. Hu br, Z. Hubacek j, N. Huske q, V. Hynek j, I. Iashvili bo, R. Illingworth au, A.S. Ito au, S. Jabeen bw, M. Jaffré p, S. Jain bo, D. Jamin o, R. Jesik ap, K. Johns ar, M. Johnson au, D. Johnston bl, A. Jonckheere au, P. Jonsson ap, J. Joshi aa, A. Juste au,4, K. Kaadze bd, E. Kajfasz o, D. Karmanov ak, P.A. Kasper au, I. Katsanos bl, R. Kehoe by, S. Kermiche o, N. Khalatyan au, A. Khanov bv, A. Kharchilava bo, Y.N. Kharzheev ai, D. Khatidze bw, M.H. Kirby ax, M. Kirsch u, J.M. Kohli aa, A.V. Kozelov al, J. Kraus bj, A. Kumar bo, A. Kupco k, T. Kurča t, V.A. Kuzmin ak, J. Kvita i, S. Lammers ay, G. Landsberg bw, P. Lebrun t, H.S. Lee ae, W.M. Lee au, J. Lellouch q, L. Li as, Q.Z. Li au, S.M. Lietti e, J.K. Lim ae, D. Lincoln au, J. Linnemann bj, V.V. Lipaev al, R. Lipton au, Y. Liu g, Z. Liu f, A. Lobodenko am, M. Lokajicek k, P. Love ao, H.J. Lubatti cb, R. Luna-Garcia af,5, A.L. Lyon au, A.K.A. Maciel b, D. Mackin bz, R. Madar r, R. Magaña-Villalba af, S. Malik bl, V.L. Malyshev ai, Y. Maravin bd, J. Martínez-Ortega af, R. McCarthy br, C.L. McGivern bc, M.M. Meijer ah, A. Melnitchouk bk, D. Menezes aw, P.G. Mercadante d, M. Merkin ak,

Search for ZZ and Zγ* Production in pp-bar Collisions at s√=1.96 TeV and Limits on Anomalous ZZZ and ZZγ* Couplings

We present a study of mu mu mu mu, eeee, and mu mu ee events using 1 fb(-1) of data collected with the D0 detector at the Fermilab Tevatron p (p) over bar Collider at root s = 1.96 TeV. Requiring t ...

Properties of L=1 B(1) and B∗(2) Mesons

This Letter presents the first strong evidence for the resolution of the excited B mesons B(1) and B(2)* as two separate states in fully reconstructed decays to B(+)(*)pi(-). The mass of B(1) is measured to be 5720.6+/-2.4+/-1.4 MeV/c(2) and the mass difference DeltaM between B(2)* and B(1) is 26.2+/-3.1+/-0.9 MeV/c;{2}, giving the mass of the B(2)* as 5746.8+/-2.4+/-1.7 MeV/c(2). The production rate for B(1) and B(2)* mesons is determined to be a fraction (13.9+/-1.9+/-3.2)% of the production rate of the B+ meson.

Search for excited muons in pp¯ collisions at √s=1.96 TeV

We present the results of a search for the production of an excited state of the muon, {mu}*, in proton antiproton collisions at {radical}s = 1.96 TeV. The data have been collected with the D0 experiment at the Fermilab Tevatron Collider and correspond to an integrated luminosity of approximately 380 pb{sup -1}. We search for {mu}* in the process p{bar p} {yields} {mu}*{nu}, with the {mu}* subsequently decaying to a muon plus photon. No excess above the standard model expectation is observed in data. Interpreting our data in the context of a model that describes {mu}* production by four-fermion contact interactions and {mu}* decay via electroweak processes, we exclude production cross sections higher than 0.057 pb-0.112 pb at the 95% confidence level, depending on the mass of the excited muon. Choosing the scale for contact interactions to be {Lambda} = 1 TeV, excited muon masses below 618 GeV are excluded.

Search for Higgs Boson Production in Dilepton and Missing Energy Final States with 5.4 fb(−1) of pp-bar Collisions at s√=1.96 TeV

A search for the standard model Higgs boson is presented using events with two charged leptons and large missing transverse energy selected from 5.4 fb-1 of integrated luminosity in p-pbar collisions at sqrt(s)=1.96 TeV collected with the D0 detector at the Fermilab Tevatron Collider. No significant excess of events above background predictions is found, and observed (expected) upper limits at 95% confidence level on the rate of Higgs boson production are derived that are a factor of 1.55 (1.36) above the predicted standard model cross section at Higgs boson mass of 165 GeV.

Measurement of the Zγ→νν-bar γ Production Cross Section and Limits on Anomalous ZZγ and Zγγ Couplings in pp-bar Collisions at s√=1.96 TeV

We present the first observation of the Zgamma to nunugamma process at the Tevatron at 5.1 standard deviations significance, based on 3.6 fb-1 of integrated luminosity collected with the D0 detector at the Fermilab Tevatron ppbar Collider at sqrt{s} = 1.96 TeV. The measured Zgamma cross section multiplied by the branching fraction of Z to nunu is 32 +- 9 (stat.+syst.) +- 2 (lumi.) fb for the photon ET > 90 GeV. It is in agreement with the standard model prediction of 39 +- 4 fb. We set the most restrictive limits on anomalous trilinear Zgammagamma and ZZgamma gauge boson couplings at a hadron collider to date, with three constraints being the worlds strongest.