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 describe a search for Z boson pair production in p (cid:1) p collisions at ffiffiffi s p ¼ 1 : 96 TeV with the D0 detector at the Fermilab Tevatron Collider using a data sample corresponding to an integrated luminosity of 2 : 7 fb (cid:1) 1 . Using the final state decay ZZ ! ‘ þ ‘ (cid:1) (cid:1) (cid:1) (cid:1) (where ‘ ¼ e or (cid:2) ) we find a signal with a 2.6 standard deviations significance (2.0 expected) corresponding to a cross section of (cid:3) ð p (cid:1) p ! ZZ þ X Þ ¼ 2 : 01 (cid:2) 0 : 93 ð stat Þ (cid:2) 0 : 29 ð sys Þ pb .

Limits on anomalous WWg and WWZ couplings from WWÕWZ\en j j production B. Abbott, M. Abolins, V. Abramov, B. S. Acharya, 13 D. L. Adams, 54 M. Adams, 30 S. Ahn, V. Akimov, G. A. Alves, N. Amos, E. W. Anderson, 36 M. M. Baarmand, 49 V. V. Babintsev, 19 L. Babukhadia, 49 A. Baden, 40 B. Baldin, S. Banerjee, 13 J. Bantly, 53 E. Barberis, 22 P. Baringer, 37 J. F. Bartlett, 29 U. Bassler, 9 A. Belyaev, 18 S. B. Beri, G. Bernardi, 9 I. Bertram, 20 V. A. Bezzubov, 19 P. C. Bhat, 29 V. Bhatnagar, 11 M. Bhattacharjee, 49 G. Blazey, 31 S. Blessing, 27

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.

The performance of the D0 experiment forward muon scintillation counters system during Run II of the Tevatron from 2001 to 2011 is described. The system consists of 4214 scintillation counters in six layers. The long term stability of the counters amplitude response determined using LED calibration system and muons produced in proton–antiproton collisions is presented. The averaged signal amplitude for counters of all layers has gradually decreased over ten years by 11%. The reference timing, determined using LED calibration, was stable within 0.26 ns. Averaged value of muon timing peak position was used for periodic D0 clock signal adjustments to compensate seasonal drift caused by temperature variations. Counters occupancy for different triggers in physics data collection runs and for minimum bias triggers are presented. The single muon yields versus time and the luminosity dependence of yields were stable for the forward muon system within 1% over 10 years.

Using data corresponding to an integrated luminosity of 1.3 fb^-1, we observe a narrow mass state decaying into Upsilon(1S)+gamma, where the Upsilon(1S) meson is detected by its decay into a pair of oppositely charged muons, and the photon is identified through its conversion into an electron-positron pair. The significance of this observation is 5.6 standard deviations. The mass of the state is centered at 10.551 \pm 0.014 (stat.) \pm 0.017 (syst.) GeV/c^2, which is consistent with that of the state recently observed by the ATLAS Collaboration.

Zγ production and limits on anomalous ZZγ and Zγγ couplings in p¯ p collisions at √ s = 1.96 TeV

We describe a model independent search for physics beyond the standard model in lepton final states. We examine 117 final states using 1.1 fb$^{-1}$ of $p \bar{p}$ collisions data at $\sqrt{s} = 1.96$ TeV collected with the D0 detector. We conclude that all observed discrepancies between data and model can be attributed to uncertainties in the standard model background modeling, and hence we do not see any evidence for physics beyond the standard model.