2011 QCD and High Energy Interactions - Rencontres de Moriond ...

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2 Events/2GeV/c 50 40 30 20 10 CMS Preliminary s = 7 TeV, L = 36 pb -1 Data tt Z+b Z+c Z+l High Efficiency b-tagging 0 60 70 80 90 100 110 120 2 M + - (GeV/c ) l l ) 2 Events / ( 0.167 GeV/c 35 30 25 20 15 10 5 CMS Preliminary -1 s = 7 TeV, L = 36 pb Data b-jets c-jets l-jets High efficiency b-tagging 0 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 2 Secondary vertex mass (GeV/c ) Figure 4: Di-lepton mass (left) and secondary vertex mass (right) of events passing the HE selection compared to the simulation. the HE selection. Results are summarised in Table 1 for the high-efficiency and high-purity selections. Values expected from simulation and theory are also given. Table 1: Ratio R = σ(pp→Z+b+X) from data and from MadGraph samples, and expected value from NLO theory. σ(pp→Z+j+X) Sample R(Z → ee) (%), p e T > 25 GeV, |η e | < 2.5 R(Z → µµ) (%), p µ T > 20 GeV, |ηµ | < 2.1 Data HE 4.3 ± 0.6(stat) ± 1.1(syst) 5.1 ± 0.6(stat) ± 1.3(syst) Data HP 5.4 ± 1.0(stat) ± 1.2(syst) 4.6 ± 0.8(stat) ± 1.1(syst) MadGraph 5.1 ± 0.2(stat) ± 0.2(syst) ± 0.6(theory) 5.3 ± 0.1(stat) ± 0.2(syst) ± 0.6(theory) MCFM 10 4.3 ± 0.5(theory) 4.7 ± 0.5(theory) 5 Conclusions Several studies of the production of jets in association with W and Z bosons in pp collisions at a centre-of-mass energy of 7 TeV using 36 pb −1 of collected data have been presented. All measurements, including the jet rates, the polarization of W and the production of b-quarks with Z bosons, are in agreement with Standard Model expectations. The precision reached in these analyses involving lepton, jet and MET reconstruction, and b-tagging, clearly establishes the readiness of the CMS experiment for searches beyond the Standard Model. References 1. CMS Collaboration, CMS PAS EWK-10-012 2. CMS Collaboration, arXiv:1104.3829v1 [hep-ex] 3. CMS Collaboration, CMS PAS EWK-10-015 4. CMS Collaboration, JINST 3:S08004 (2008). 5. M. Cacciari, G. P. Salam, and G. Soyez, JHEP 0804:063 (2008). 6. Z. Berg et al., arXiv:1103.5445v2 [hep-ph] 7. CMS Collaboration, CMS PAS JME-10-010 8. J. Alwall et al., JHEP 09, 028 (2007) 9. T. Sjöstrand, S. Mrenna, and P. Skands, JHEP 05, 026 (2006) 10. J. M. Campbell and R. K. Ellis, PRD 62, 114012 (2000)
TEVATRON RESULTS ON MULTI-PARTON INERACTIONS N.B. SKACHKOV Joint Institute for Nuclear Research, Joliot-Curie 6, Dubna, Russia The D0 experiment used a sample of γ + 3 jets events (collected in RunII with an integrated luminosity L about 1fb −1 ) to determine the fraction of events with double parton (DP) scattering in a single p¯p collision at √ s = 1.96 TeV. The DP fraction (fDP) and effective cross section (σeff), a process-independent scale parameter related to the parton density inside the nucleon, are measured in three intervals of the second (ordered in pT) jet transverse momentum p jet2 T within the range 15 ≤ p jet2 T ≤ 30 GeV. In this range, fDP varies between 0.23 ≤ fDP ≤ 0.47, while σeff has the average value σ ave eff = 16.4 ± 0.3(stat) ± 2.3(syst) mb. The samples of inclusive γ + 2 jet and γ + 3 jet events are also used to measure cross sections as a function of the azimuthal angle between the transverse momentum (pT) of the γ+leading jet system and pT of the other jet for γ + 2 jet, or pT sum of the two other jets for γ + 3 jet events. The results are compared to different models of multiple parton interactions (MPI) in the pythia and sherpa Monte Carlo (MC) generators. The data strongly indicate a contribution from events with double parton interactions and are in good agreement with predictions provided by the new pythia MPI models with pT-ordered showers and by sherpa with the default MPI model. The γ + 2 jet data are also used to determine the fraction of events with DP interactions as a function of the azimuthal angle binned in the second jet pT. It is commonly assumed that high energy inelastic scattering of nucleons occurs through a single parton-parton interaction and the contribution from double (A and B) parton collisions (see its schematic view in Fig.1 a)) is a negligible one. The DP cross section can be defined as: σDP ≡ σA σ B σeff Here σA and σB are the cross sections of two independent partonic scatterings A and B. The normalization factor σeff (it has the units of cross section) is a process-independent parameter that can be related to the parton spatial density (see 1,2,3,4,5,6 and the references to basic theoretical papers presented there). Two years ago there were only four published dedicated measurements of double parton scattering in hadron collisions: the AFS experiment in pp collisions at √ s = 63 GeV 1 , UA2 in p¯p collisions at √ s = 630 GeV 2 and by CDF in p¯p collisions at √ s = 1.8 TeV 3 , 4 . The four-jet final state has been used in the first three measurements while the last, the most precise one CDF measurement 4 , have used γ/π0 + 3 jets events (accumulated with L =16 pb−1 ) having the pT of the second jet (ordered in pT) within the interval 5 and pγ T T GeV. The substitution of one jet by photon leads to an order of magnitude improvement in the ratio of the signal to background over the earlier CDF study 4 . A new technique for extracting σeff was proposed in 4 . It uses only quantities determined from data analysis and minimizes the impact of theoretical assumptions used in previous three measurements with a 4-jet final state 1,2,3 . (1) > 16
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2011 QCD and High Energy Interactio
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Proceedings of the XLVIth RENCONTRE
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2011 RENCONTRES DE MORIOND The XLVI
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Foreword Contents 1. Higgs Searches
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1. Higgs
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95% CL Limit/SM 10 1 Tevatron Run I
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Events/5 GeV 6 10 5 10 4 10 3 10 2
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Events / 0.5 CDF Run II Preliminary
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For the most sensitive sub-channel
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Table 1: Table listing the various
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various SM Higgs mass hypotheses. T
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constraints on parameters are given
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Figure 2: Invariant mass of the ele
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Figure 4: CDF Exclusion limits for
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Table 1: Main phases of 2010 commis
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Table 4: Parameter list for early (
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luminosity of 1.2×10 33 cm −2 s
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2 QCD Analysis settings HERA PDFs a
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min 2 - 2 20 15 10 5 0 H1 and ZEUS
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SM σ / σ 95% CL Limit on 3 10 2 1
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NNLO σ/ σSM 95% CL Upper Bound on
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the report of this working group. I
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2.3 The impact of different PDF par
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SUSY Searches at the Tevatron Ph. G
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on the quality (loose or tight) and
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SUSY searches at ATLAS N. Barlow, o
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channel. These results are combined
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Figure 2: The top left plot shows t
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2010 data. Analysis techniques for
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as main discriminator between event
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sign leptons is particularly intere
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N of events 5 10 DATA 10 4 3 10 10
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) [pb] ν e → B(W’ × σ 10 1 -
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2 Searches in the dijet final state
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ing that the neutrinos were the onl
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The Quasi-Classical Model in SU(N)
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g (γ µ kµ) γ µ Aa µ g (pk)
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3. Top
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of their vertex with respect to the
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of about 9%. 3.1 Differential Cross
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Figure 5: Summary of most recent CD
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the minimum number of jets identifi
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where f’s are probability functio
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hood technique, with a simultaneous
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momentum direction of the b quark f
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Events 200 150 100 50 -1 DØ L=5.4
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after all corrections in the M t¯t
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for prompt J/ψ under the fully tra
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2 Events / 20 MeV/c 50 40 30 20 10
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ATLAS - consists of four parts (mon
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5 D mesons High cross-sections of D
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μ +X') [nb/GeV] → b+X → (pp T
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GeV) μ |
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HEAVY FLAVOUR IN A NUTSHELL Robert
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Figure 1: Overlapping constraints o
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Figure 3: Constraints on new physic
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RECENT B PHYSICS RESULTS FROM THE T
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(IP) distributions are fitted separ
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decays CDF extracts Using a 5.94 fb
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Search for B 0 s → µ+ µ − and
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Ref. 10,11 . The expected GL distri
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IN PURSUIT OF NEW PHYSICS WITH B DE
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τK + K −/τBs 1.01 1.00 0.99 0.9
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CHARMLESS HADRONIC B-DECAYS AT BABA
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surements (fL ∼ 0.5). Several att
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Estimating the Higher Order Hadroni
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the resulting exponent suggests to
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The counterpart of the ground-state
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(a) Tree level signal decay b ¯Bs
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the B0 d system LHCb profits from i
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This result is based on averaging o
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y non-perturbative effects. Using t
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e M(Dπ) distributions obtained D +
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CHARM PHYSICS RESULTS AND PROSPECTS
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LHCb is working towards its first m
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Two body hadronic D decays Yu Fushe
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where the effective coefficients aA
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6. J. J. Sakurai, Phys. Rev. 156, 1
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states: 6π, 2K4π, 4K2π, KSK3π 1
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egion of X(3872), which corresponds
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Figure 1: The π 0 recoil mass spec
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η → π + π − π 0 η ′ →
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conservation. This second principle
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many of them come from gluon nonper
Page 179 and 180: Latest Jets Results from the Tevatr
Page 181 and 182: in for the inclusive trijet event s
Page 183 and 184: RECENT RESULTS ON JETS FROM CMS F.
Page 185 and 186: dy (pb/GeV) /dp 2 d 10 10 10 9 10
Page 187 and 188: RECENT RESULTS ON JETS WITH ATLAS G
Page 189 and 190: | y| < 0.3 ATLAS Preliminary 2.1 <
Page 191 and 192: EPOS 2 and LHC Results TanguyPierog
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Page 195 and 196: ABOUT THE HELIX STRUCTURE OF THE LU
Page 197 and 198: Figure 2: Left: Correlations betwee
Page 199 and 200: Improving NLO-parton shower matched
Page 201 and 202: due to the inclusion of higher orde
Page 203 and 204: New Results in Soft Gluon Physics C
Page 205 and 206: Figure 2: Spacetime depiction of Dr
Page 207 and 208: Central Exclusive Meson Pair Produc
Page 209 and 210: in the CEP cross section. However i
Page 211 and 212: AN AVERAGE b-QUARK FRAGMENTATION FU
Page 213 and 214: 1/N dN/dx 3.5 3 2.5 2 1.5 1 0.5 ALE
Page 215 and 216: W + W + jj at NLO in QCD: an exotic
Page 217 and 218: Σ fb Σ fb 3.5 3.0 2.5 2.0 0.65 0.
Page 219 and 220: W/Z+Jets and W/Z+HF Production at t
Page 221 and 222: Figure 2: Measured inclusive jet di
Page 223 and 224: W and Z physics with the ATLAS dete
Page 225 and 226: SHERPA 9 MC generators but not by P
Page 227 and 228: W/Z + Jets results from CMS V. CIUL
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Page 233 and 234: iterative midpoint cone algorithm w
Page 235 and 236: INVESTIGATIONS OF DOUBLE PARTON SCA
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Page 239 and 240: Figure 4: Two-dimensional distribut
Page 241 and 242: SOFT QCD RESULTS FROM ATLAS AND CMS
Page 243 and 244: as a function of multiplicity for t
Page 245 and 246: Determination of αS using hadronic
Page 247 and 248: α S (m Z 0) 0.15 0.14 0.13 0.12 0.
Page 249 and 250: Reaching beyond NLO in processes wi
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Page 253 and 254: Nonlocal Condensate Model for QCD S
Page 255 and 256: The lower bound for the integration
Page 257 and 258: AN ALTERNATIVE SUBTRACTION SCHEME F
Page 259 and 260: where MBorn,g is the underlying Bor
Page 261 and 262: THE NNPDF2.1 PARTON SET F. CERUTTI
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Page 265 and 266: HOLOGRAPHIC DESCRIPTION OF HADRONS
Page 267 and 268: ∫ SYM = κ d 4 ( 1 xdzTr 2 h(z)F
Page 269 and 270: Nuclear matter and chiral phase tra
Page 271 and 272: fact that for Nc ≫ 3 a gas of fre
Page 273 and 274: Recent Results on Light Hadron Spec
Page 275 and 276: Figure 3: Mass spectrum fitting wit
Page 277 and 278: MEASUREMENT OF THE J/ψ INCLUSIVE P
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STUDY OF Ke4 DECAYS IN THE NA48/2 E
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photons were accepted while particl
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6. Structure Functions Diffraction
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2 Hadronic Final States and Diffrac
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3 Summary A brief overview of recen
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Using HERA Data to Determine the In
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k f n 0.4 0.2 0 -0.2 0.4 0.2 0 -0.2
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The singular term, on the other han
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Pomeron Kernel: The leading order B
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DIFFRACTION, SATURATION AND pp CROS
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In Ref. 6 , the saturated Froissart
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Transverse Energy Flow with Forward
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1/N d dE t /dη 0.1 0.09 0.08 0.07
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7. Heavy Ions
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dη)/(0.5〈 N 〉 ) part ch (dN 10
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) 3 (fm long R side R out R 400 350
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correlation density is computed as
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Away-side gaussian width 1.4 1.2 1
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Figure 1: (a) J/ψ rapidity distrib
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lower x, or forward rapidity one ex
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φ ∆ /d assoc dN trig 1/N 0.5 0.4
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AA,Pythia I 2.5 2.0 1.5 1.0 0.5 0.0
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(1/N ) dN/dA evt J φ Δ ) dN/d (1/
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[GeV] Tower ET Σ 50 45 40 35 30 25
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3 Results 3.1 Dijet Properties in p
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(GeV/c) (GeV/c) T T p < 40 20
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wheredσm(N +N → h+X)/dp Tdy isth
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R AA 0.6 0.5 0.4 0.3 0.2 0.1 0 0.5
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Here D is the diffusion coefficient
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The effect of triangular flow in je
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When both trigger and associated pa
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The first Z boson measurement in th
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Figure 1: Dimuon invariant mass spe
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2. V. Kartvelishvili, R. Kvatadze a
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esolution [ µ m] ! r 0 d 300 250 2
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Figure 5: Differential transverse m
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Figure 1: Average nuclear modificat
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Another way of using direct photons
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Pb R g 2 Nuclear Modifications for
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q T 1/R AA 1.6 1.4 1.2 1 0.8 LO Fra
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] 2 > [g/cm max
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Methods (a) and (c) constrain the e
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EXPERIMENTAL SUMMARY: ENTERING THE
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ut also for valence quarks involved
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The sensitivity to Standard Model H
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Figure 10: Top pair mass spectrum m
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Figure 13: Particle densities (left
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4 Low energy precision Spectroscopy
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asymmetries associated to Bd and Bs
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XLVIth Rencontres de Moriond QCD an
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