We report an improved measurement of the valence u and d quark distributions from the forward-backward asymmetry in the Drell-Yan process using 8.6 fb(-1) of data collected with the D0 detector in p (p) over bar collisions at root s = 1.96. This analysis provides the values of new structure parameters that are directly related to the valence up and down quark distributions in the proton. In other experimental results measuring the quark content of the proton, d quark contributions are mixed with those from other quark flavors. In this measurement, the u and d quark contributions are separately extracted by applying a factorization of the QCD and electroweak portions of the forward-backward asymmetry.

I discuss several novel and unexpected aspects of quantum chromodynamics. These include: (a) the nonperturbative origin of intrinsic strange, charm and bottom quarks in the nucleon at large x; the breakdown of pQCD factorization theorems due to the lensing effects of initialand final-state interactions; (b) important corrections to pQCD scaling for inclusive reactions due to processes in which hadrons are created at high transverse momentum directly in the hard processes and their relation to the baryon anomaly in high-centrality heavy-ion collisions; and (c) the nonuniversality of quark distributions in nuclei. I also discuss some novel theoretical perspectives in QCD: (a) lightfront holography – a relativistic color-confining first approximation to QCD based on the AdS/CFT correspondence principle; (b) the principle of maximum conformality – a method which determines the renormalization scale at finite order in perturbation theory yielding scheme independent results; (c) the replacement of quark and gluon vacuum condensates by “in-hadron condensates” and how this helps to resolves the conflict between QCD vacuum and the cosmological constant.

We present a study of the normalized transverse momentum distribution of W bosons produced in p ¯ p collisions, using data corresponding to an integrated luminosity of 4 . 35 fb − 1 collected with the D0 detector at the Fermilab Tevatron collider at ffiffiffi s p ¼ 1 . 96 TeV. The measurement focuses on the transverse momentum region below 15 GeV, which is of special interest for electroweak precision measurements; it relies on the same detector calibration methods which were used for the precision measurement of the W boson mass. The measured distribution is compared to different QCD predictions and a procedure is given to allow the comparison of any further theoretical models to the D0 data.

We present various properties of the production of the X(3872) and psi(2S) states based on 10.4 fb(-1) collected by the D0 experiment in Tevatron p (p) over bar collisions at root s = 1.96 TeV. For both states, we measure the nonprompt fraction f(NP) of the inclusive production rate due to decays of b-flavored hadrons. We find the f(NP) values systematically below those obtained at the LHC. The f(NP) fraction for psi(2S) increases with transverse momentum, whereas for the X(3872) it is constant within large uncertainties, in agreement with the LHC results. The ratio of prompt to nonprompt psi(2S) production, ( 1 - f(NP))/f(NP), decreases only slightly going from the Tevatron to the LHC, but for the X(3872), this ratio decreases by a factor of about 3. We test the soft-pion signature of the X(3872) modeled as a weakly bound charm-meson pair by studying the production of the X(3872) as a function of the kinetic energy of the X(3872) and the pion in the X(3872)pi center-of-mass frame. For a subsample consistent with prompt production, the results are incompatible with a strong enhancement in the production of the X(3872) at the small kinetic energy of the X(3872) and the pi in the X(3872)pi center-of-mass frame expected for the X + soft-pion production mechanism. For events consistent with being due to decays of b hadrons, there is no significant evidence for the soft-pion effect, but its presence at the level expected for the binding energy of 0.17 MeV and the momentum scale Lambda = M(pi) is not ruled out.

We study the production of the exotic charged charmoniumlike state Z(c)(+/-)(3900) in p (p) over bar collisions through the sequential process psi(4260) -> Z(c)(+/-)(3900)(pi)(-/+), Z(c)(+/-)(3900) -> J/psi pi(+/-). Using the subsample of candidates originating from semi-inclusive weak decays of b-flavored hadrons, we measure the invariant mass and natural width to be M = 3902.6(-5.0)(+5.2)(stat)(-1.4)(+3.3)(syst) MeV and Gamma = 32(-21)(+28)(stat)(-7)(+26)(syst) MeV, respectively. We search for prompt production of the Z(c)(+/-)(3900) through the same sequential process. No significant signal is observed, and we set an upper limit of 0.70 at the 95% credibility level on the ratio of prompt production to the production via b-hadron decays. The study is based on 10.4 fb(-1) of p (p) over bar collision data collected by the D0 experiment at the Fermilab Tevatron collider.

V.M. Abazov, B. Abbott, B.S. Acharya, M. Adams, T. Adams, J.P. Agnew, G.D. Alexeev, G. Alkhazov, A. Alton, A. Askew, S. Atkins, K. Augsten, V. Aushev, Y. Aushev, C. Avila, F. Badaud, L. Bagby, B. Baldin, D.V. Bandurin, S. Banerjee, E. Barberis, P. Baringer, J.F. Bartlett, U. Bassler, V. Bazterra, A. Bean, M. Begalli, L. Bellantoni, S.B. Beri, G. Bernardi, R. Bernhard, I. Bertram, M. Besançon, R. Beuselinck, P.C. Bhat, S. Bhatia, V. Bhatnagar, G. Blazey, S. Blessing, K. Bloom, A. Boehnlein, D. Boline, E.E. Boos, G. Borissov, M. Borysova, A. Brandt, O. Brandt, M. Brochmann, R. Brock, A. Bross, D. Brown, X.B. Bu, M. Buehler, V. Buescher, V. Bunichev, S. Burdin, C.P. Buszello, E. Camacho-Pérez, B.C.K. Casey, H. Castilla-Valdez, S. Caughron, S. Chakrabarti, K.M. Chan, A. Chandra, E. Chapon, G. Chen, S.W. Cho, S. Choi, B. Choudhary, S. Cihangir, D. Claes, J. Clutter, M. Cooke, W.E. Cooper, M. Corcoran, F. Couderc, M.-C. Cousinou, J. Cuth, D. Cutts, A. Das, G. Davies, S.J. de Jong, 30 E. De La Cruz-Burelo, F. Déliot, R. Demina, D. Denisov, S.P. Denisov, S. Desai, C. Deterre, K. DeVaughan, H.T. Diehl, M. Diesburg, P.F. Ding, A. Dominguez, A. Drutskoy, A. Dubey, L.V. Dudko, A. Duperrin, S. Dutt, M. Eads, D. Edmunds, J. Ellison, V.D. Elvira, Y. Enari, H. Evans, A. Evdokimov, V.N. Evdokimov, A. Fauré, L. Feng, T. Ferbel, F. Fiedler, F. Filthaut, 30 W. Fisher, H.E. Fisk, M. Fortner, H. Fox, J. Franc, S. Fuess, P.H. Garbincius, A. Garcia-Bellido, J.A. Garćıa-González, V. Gavrilov, W. Geng, 57 C.E. Gerber, Y. Gershtein, G. Ginther, O. Gogota, G. Golovanov, P.D. Grannis, S. Greder, H. Greenlee, G. Grenier, Ph. Gris, J.-F. Grivaz, A. Grohsjean, S. Grünendahl, M.W. Grünewald, T. Guillemin, G. Gutierrez, P. Gutierrez, J. Haley, L. Han, K. Harder, A. Harel, J.M. Hauptman, J. Hays, T. Head, T. Hebbeker, D. Hedin, H. Hegab, A.P. Heinson, U. Heintz, C. Hensel, I. Heredia-De La Cruz, K. Herner, G. Hesketh , M.D. Hildreth, R. Hirosky, T. Hoang, J.D. Hobbs, B. Hoeneisen, J. Hogan, M. Hohlfeld, J.L. Holzbauer, I. Howley, Z. Hubacek, 15 V. Hynek, I. Iashvili, Y. Ilchenko, R. Illingworth, A.S. Ito, S. Jabeen, M. Jaffré, A. Jayasinghe, M.S. Jeong, R. Jesik, P. Jiang, K. Johns, E. Johnson, M. Johnson, A. Jonckheere, P. Jonsson, J. Joshi, A.W. Jung, A. Juste, E. Kajfasz, D. Karmanov, I. Katsanos, M. Kaur, R. Kehoe, S. Kermiche, N. Khalatyan, A. Khanov, A. Kharchilava, Y.N. Kharzheev, I. Kiselevich, J.M. Kohli, A.V. Kozelov, J. Kraus, A. Kumar, A. Kupco, T. Kurča, V.A. Kuzmin, S. Lammers, P. Lebrun, H.S. Lee, S.W. Lee, W.M. Lee, X. Lei, J. Lellouch, D. Li, H. Li, L. Li, Q.Z. Li, J.K. Lim, D. Lincoln, J. Linnemann, V.V. Lipaev, R. Lipton, H. Liu, Y. Liu, A. Lobodenko, M. Lokajicek, R. Lopes de Sa, R. Luna-Garcia, A.L. Lyon, A.K.A. Maciel, R. Madar, R. Magaña-Villalba, S. Malik, V.L. Malyshev, J. Mansour, J. Mart́ınez-Ortega, R. McCarthy, C.L. McGivern, M.M. Meijer, 30 A. Melnitchouk, D. Menezes, P.G. Mercadante, M. Merkin, A. Meyer, J. Meyer, F. Miconi, N.K. Mondal, M. Mulhearn, E. Nagy, M. Narain, R. Nayyar, H.A. Neal, J.P. Negret, P. Neustroev, H.T. Nguyen, T. Nunnemann, J. Orduna, N. Osman, A. Pal, N. Parashar, V. Parihar, S.K. Park, R. Partridge, N. Parua, A. Patwa, B. Penning, M. Perfilov, Y. Peters, K. Petridis, G. Petrillo, P. Pétroff, M.-A. Pleier, V.M. Podstavkov, A.V. Popov, M. Prewitt, D. Price, N. Prokopenko, J. Qian, A. Quadt, B. Quinn, P.N. Ratoff, I. Razumov, I. Ripp-Baudot, F. Rizatdinova, M. Rominsky, A. Ross, C. Royon, P. Rubinov, R. Ruchti, G. Sajot, A. Sánchez-Hernández, M.P. Sanders, A.S. Santos, G. Savage, M. Savitskyi, L. Sawyer, T. Scanlon, R.D. Schamberger, Y. Scheglov, H. Schellman, 48 M. Schott, C. Schwanenberger, R. Schwienhorst, J. Sekaric, H. Severini, E. Shabalina, V. Shary, S. Shaw, A.A. Shchukin, O. Shkola, V. Simak, P. Skubic, P. Slattery, G.R. Snow, J. Snow, S. Snyder, S. Söldner-Rembold, L. Sonnenschein, K. Soustruznik, J. Stark, N. Stefaniuk, D.A. Stoyanova, M. Strauss, L. Suter, P. Svoisky, M. Titov, V.V. Tokmenin, Y.-T. Tsai, D. Tsybychev, B. Tuchming, C. Tully, L. Uvarov, S. Uvarov, S. Uzunyan, R. Van Kooten, W.M. van Leeuwen, N. Varelas, E.W. Varnes, I.A. Vasilyev, A.Y. Verkheev, L.S. Vertogradov, M. Verzocchi, M. Vesterinen, D. Vilanova, P. Vokac, H.D. Wahl, C. Wang, M.H.L.S. Wang, J. Warchol, G. Watts, M. Wayne, J. Weichert, L. Welty-Rieger, M.R.J. Williams, G.W. Wilson, M. Wobisch, D.R. Wood, T.R. Wyatt, Y. Xie, R. Yamada, S. Yang, T. Yasuda, Y.A. Yatsunenko, W. Ye, Z. Ye, H. Yin, K. Yip, S.W. Youn, J.M. Yu,

We present evidence for the exotic charged charmoniumlike state Z(c)(+/-)(3900) decaying to J/psi pi(+/-) in semi-inclusive weak decays of b-flavored hadrons. The signal is correlated with a parent J/psi pi(+)pi(-) system in the invariant-mass range 4.2-4.7 GeV that would include the exotic structure Y(4260). The study is based on 10.4 fb(-1) of p (p) over bar collision data collected by the D0 experiment at the Fermilab Tevatron collider.

In this work, the results of the measurements of characteristics of 40-cm and 2-m scintillation counters irradiated by a particle beam with a momentum of 7 GeV/c from the accelerator of the Institute for High Energy Physics are presented. The scintillators used in counters are BC-404 and BC-408 scintillators. The counters are viewed from both ends by R1828-01 photomultiplier tubes. The PMT signal spectra are well described by a convolution of the Landau and Gaussian distributions. Their width is determined mainly by fluctuations of ionization energy losses. The time distributions of the signals obey the Gaussian law. For the 40-cm counter, the time resolution is σ( T ) = 88 ps; for the 2-m counter, it varies from 120–160 ps in its center to ~100 ps near the end.

We present a measurement of the effective weak mixing angle parameter sin^{2}θ_{eff}^{ℓ} in pp[over ¯]→Z/γ^{*}→μ^{+}μ^{-} events at a center-of-mass energy of 1.96 TeV, collected by the D0 detector at the Fermilab Tevatron Collider and corresponding to 8.6  fb^{-1} of integrated luminosity. The measured value of sin^{2}θ_{eff}^{ℓ}[μμ]=0.23016±0.00064 is further combined with the result from the D0 measurement in pp[over ¯]→Z/γ^{*}→e^{+}e^{-} events, resulting in sin^{2}θ_{eff}^{ℓ}[comb]=0.23095±0.00040. This combined result is the most precise measurement from a single experiment at a hadron collider and is the most precise determination using the coupling of the Z/γ^{*} to light quarks.

Drell-Yan lepton pairs produced in the process p (p) over bar -> l(+)l(-) + X through an intermediate gamma*/Z boson have an asymmetry in their angular distribution related to the spontaneous symmetry breaking of the electroweak force and the associated mixing of its neutral gauge bosons. The CDF and D0 experiments have measured the effective-leptonic electroweak mixing parameter sin(2) theta(lept)(eff) using electron and muon pairs selected from the full Tevatron proton-antiproton data sets collected in 2001-2011, corresponding to 9-10 fb(-1) of integrated luminosity. The combination of these measurements yields the most precise result from hadron colliders, sin(2)theta(lept)(eff) = 0.23148 +/- 0.00033. This result is consistent with, and approaches in precision, the best measurements from electron-positron colliders. The standard model inference of the on-shell electroweak mixing parameter sin(2) theta(W), or equivalently the W-boson mass M-W, using the ZFITTER software package yields sin(2) theta(W) = 0.22324 +/- 0.00033 or equivalently, M-W = 80.367 +/- 0.017 GeV/c(2).

We present a study of the X-+/-(5568) using semileptonic decays of the B-s(0) meson using the full run II integrated luminosity of 10.4 fb(-1) in proton-antiproton collisions at a center of mass energy of 1.96 TeV collected with the DO detector at the Fermilab Tevatron Collider. We report evidence for a narrow structure, X-+/-(5568), in the decay sequence X-+/-(5568) -> B-s(0) pi(+/-) where B-s(0)-> mu(-/+) (DsX)-X-+/-, D-s(+/-)-> phi pi(+/-)which is consistent with the previous measurement by the DO Collaboration in the hadronic decay mode, X-+/-(5568) -> B-s(0)pi(+/-) where B-s(0) -> J/psi phi. The mass and width of this state are measured using a combined fit of the hadronic and semileptonic data, yielding m = 5566.9(-3.1)(+3.2)(stat)(-1.2)(+0.6)(syst) MeV/c(2), Gamma = 18.6(-6.1)(+7.9)(stat)(-3.8)(+3.5) (syst) McV/c(2) with a significance of 6.7 sigma.

We present a study of the ${X}^{\ifmmode\pm\else\textpm\fi{}}(5568)$ using semileptonic decays of the ${B}_{s}^{0}$ meson using the full run II integrated luminosity of $10.4\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ in proton-antiproton collisions at a center of mass energy of 1.96 TeV collected with the D0 detector at the Fermilab Tevatron Collider. We report evidence for a narrow structure, ${X}^{\ifmmode\pm\else\textpm\fi{}}(5568)$, in the decay sequence ${X}^{\ifmmode\pm\else\textpm\fi{}}(5568)\ensuremath{\rightarrow}{B}_{s}^{0}{\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$ where ${B}_{s}^{0}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{\ensuremath{\mp}}{D}_{s}^{\ifmmode\pm\else\textpm\fi{}}\mathrm{X}$, ${D}_{s}^{\ifmmode\pm\else\textpm\fi{}}\ensuremath{\rightarrow}\ensuremath{\phi}{\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$ which is consistent with the previous measurement by the D0 Collaboration in the hadronic decay mode, ${X}^{\ifmmode\pm\else\textpm\fi{}}(5568)\ensuremath{\rightarrow}{B}_{s}^{0}{\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$ where ${B}_{s}^{0}\ensuremath{\rightarrow}J/\ensuremath{\psi}\ensuremath{\phi}$. The mass and width of this state are measured using a combined fit of the hadronic and semileptonic data, yielding $m={5566.9}_{\ensuremath{-}3.1}^{+3.2}{(\mathrm{stat})}_{\ensuremath{-}1.2}^{+0.6}(\mathrm{syst})\text{ }\text{ }\mathrm{MeV}/{c}^{2}$, $\mathrm{\ensuremath{\Gamma}}={18.6}_{\ensuremath{-}6.1}^{+7.9}{(\mathrm{stat})}_{\ensuremath{-}3.8}^{+3.5}(\mathrm{syst})\text{ }\text{ }\mathrm{MeV}/{c}^{2}$ with a significance of $6.7\ensuremath{\sigma}$.

We present a measurement of top quark polarization in $t\bar{t}$ pair production in $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV using data corresponding to 9.7 fb$^{-1}$ of integrated luminosity recorded with the D0 detector at the Fermilab Tevatron Collider. We consider final states containing a lepton and at least three jets. The polarization is measured through the distribution of lepton angles along three axes: the beam axis, the helicity axis, and the transverse axis normal to the $t\bar{t}$ production plane. This is the first measurement of top quark polarization at Tevatron using lepton+jet final states and the first measurement of the transverse polarization in $t\bar{t}$ production. The observed distributions are consistent with standard model predictions of nearly no polarization.

We present a combination of measurements of the top quark mass by the D0 experiment in the lepton+jets and dilepton channels. We use all the data collected in Run I (1992--1996) at $\sqrt s=1.8$ TeV and Run II (2001--2011) at $\sqrt s=1.96$ TeV of the Tevatron $p \bar{p}$ collider, corresponding to integrated luminosities of 0.1 fb$^{-1}$ and 9.7 fb$^{-1}$, respectively. The combined result is: $m_t = 174.95 \pm0.40\,{\rm(stat)} \pm 0.64\,{\rm(syst)}\,{\rm{GeV}}=174.95 \pm 0.75 \, {\rm{GeV}}$.

We present the first measurement of the CP violating charge asymmetry in B-+/- -> mu(+/-)nu D-mu(0) decays using the full Run II integrated luminosity of 10.4 fb(-1) in proton-antiproton collisions collected with the D0 detector at the Fermilab Tevatron Collider. We measure a difference in the yield of B- and B+ mesons in these decays by fitting the reconstructed invariant mass distributions. This results in an asymmetry of A(mu D0) = [-0.14 +/- 0.20] %, which is consistent with standard model predictions.