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Figure 1: (a) M dependence of fπ for different s0 with λq = 0.75 GeV and c = 0.3. (b) Curve for the allowed values of c and λq that produce the pion decay constant fπ = 0.1307. (c) Q 2 dependence of the pion form factor. λq (GeV) mq (MeV) a (GeV −2 ) N1/⟨qq⟩ (GeV −4 ) N2/⟨qq⟩ (GeV −4 ) u quark 0.75 4.2 22.7 20.54 −7784.54 d quark 0.75 7.5 22.7 36.70 −7789.33 4 Summary Table 1: Parameters associated with the quarks u and d in our formalism. We have included the nonlocal quark condensates into QSR via the KL parametrization for a dressed fermion propagator, which is decomposed into the perturbative and non-perturbative pieces. The negative spectral density function implies that the contribution from higher effective quark masses is non-perturbative. The parametrization of the spectral density functions leads to the known exponential ansatz for the nonlocal condensate model in our formalism. We have analyzed the pion form factor as an example, and the results are in good agreement with the data for Q 2 between 1-10 GeV 2 . Acknowledgments This work was supported by the National Center for Theoretical Sciences and National Science Council of R.O.C. under Grant No. NSC-98-2112-M-001-015-MY3. References 1. C. Corianò, A. Radyushkin and G. Sterman, Nucl. Phys. B 405, 481 (1993) 2. A.V. Radyushkin, arXiv:hep-ph/0101227. 3. G. Källén, Helv. Phys. Acta 25, 417 (1952); H. Lehmann, Nuovo Cimento 11, 342 (1954). 4. R.C. Hsieh and H-n. Li, Phys. Lett. B 698, 140 (2011). 5. S. Mallik, Nucl. Phys. B 234, 45 (1984). 6. C. Corianò, Nucl. Phys. B 410, 90 (1993). 7. A.V. Radyushkin, arXiv:hep-ph/9406237. 8. A.P. Bakulev and S.V. Mikhailov, Z. Phys. C 68, 451 (1995); Mod. Phys. Lett. A 11, 1611 (1996); Phys. Rev. D 65, 114511 (2002). 9. A. V. Radyushkin, Phys. Lett. B 271, 218 (1991). 10. R. Alkofer and L.V. Smekal, Phys. Rept. 353, 281 (2001).
AN ALTERNATIVE SUBTRACTION SCHEME FOR NLO CALCULATIONS T. ROBENS School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, Scotland, UK C.H. CHUNG and M. KR ÄMER Institute for Theoretical Particle Physics and Cosmology, RWTH Aachen, 52056 Aachen, Germany We present a new subtraction scheme for next-to-leading order QCD calculations, where the momentum mapping and the splitting functions have been derived in the context of an improved parton shower formulation. A main advantage of our scheme is the significantly reduced number of momentum mappings in the subtraction terms compared to standard schemes. We present the major features of our scheme and discuss the process e q → e q (g) in more detail. 1 Introduction Both the further validation of the Standard Model (SM) as well as searches for new physics beyond the SM require an exact knowledge of the SM signals at at least Next-to-leading order (NLO). For precise differential predictions, these NLO corrections need to be included in Monte Carlo Event Generators. However, an increase of final state particle multiplicity in the LO process in such codes directly translates to an increase of the computational runtime. This is partially caused by the treatment of infrared (IR) singularities: For standard subtraction schemes, the number of momentum mappings and Born matrix reevaluations rapidly increases with the number of final state particles. We here present a new scheme which significantly reduces the number of the momentum mappings in the real emission subtraction terms. 2 Subtraction schemes We consider a generic jet cross-section σ with σ = σ LO + σ NLO = m dσ B + dσ m V + dσ m+1 R , (1) where σ B , σ V , and σ R denote the LO, virtual and real-emission contributions, and with m(m+1) partons in the final state in the LO (real emission) phase space. The IR poles, which are inherent in both dσ V and dσ R , cancel in the sum of these two terms; however, the individual pieces are divergent and can thus not be integrated numerically. Subtraction schemes resolve this issue by introducing local counterterms, which match the behaviour of the real-emission matrix element in each singular region. Subtracting the counterterms from the real-emission matrix elements and adding back the corresponding one-particle integrated counterparts to the virtual contribution
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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
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Latest Jets Results from the Tevatr
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in for the inclusive trijet event s
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RECENT RESULTS ON JETS FROM CMS F.
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dy (pb/GeV) /dp 2 d 10 10 10 9 10
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RECENT RESULTS ON JETS WITH ATLAS G
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| y| < 0.3 ATLAS Preliminary 2.1 <
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EPOS 2 and LHC Results TanguyPierog
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positions are randomly distributed
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ABOUT THE HELIX STRUCTURE OF THE LU
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Figure 2: Left: Correlations betwee
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Improving NLO-parton shower matched
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due to the inclusion of higher orde
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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
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Page 215 and 216: W + W + jj at NLO in QCD: an exotic
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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 231 and 232: TEVATRON RESULTS ON MULTI-PARTON IN
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: The lower bound for the integration
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
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Page 269 and 270: Nuclear matter and chiral phase tra
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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
Page 279 and 280: 2 Counts per 40 MeV/c 120 100 80 60
Page 281 and 282: STUDY OF Ke4 DECAYS IN THE NA48/2 E
Page 283 and 284: photons were accepted while particl
Page 285: 6. Structure Functions Diffraction
Page 288 and 289: 2 Hadronic Final States and Diffrac
Page 290 and 291: 3 Summary A brief overview of recen
Page 293 and 294: Using HERA Data to Determine the In
Page 295 and 296: k f n 0.4 0.2 0 -0.2 0.4 0.2 0 -0.2
Page 297: The singular term, on the other han
Page 301 and 302: Pomeron Kernel: The leading order B
Page 303 and 304: DIFFRACTION, SATURATION AND pp CROS
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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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