Quarkonium and Heavy Flavour Meson Production at 13 TeV at ATLAS - - PowerPoint PPT Presentation

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Quarkonium and Heavy Flavour Meson Production at 13 TeV at ATLAS - - PowerPoint PPT Presentation

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Quarkonium and Heavy Flavour Meson Production at 13 TeV at ATLAS Leonid Gladilin (Moscow State Univ.) on behalf of the ATLAS Collaboration 2-7 June 2016 , Krakow Outline : Introduction Charmonium ATLAS-CONF-2015-030, ATLAS-CONF-2016-0XX

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Quarkonium and Heavy Flavour Meson Production at 13 TeV at ATLAS Leonid Gladilin (Moscow State Univ.)

  • n behalf of the ATLAS Collaboration

Outline : Introduction Charmonium ATLAS-CONF-2015-030, ATLAS-CONF-2016-0XX (X(3872))

EPJ C76 (2016) 283, JHEP 09 (2014) 079, JHEP 07 (2014) 154

Beauty mesons ATLAS-CONF-2015-064, PRL 115 (2015) 262001,

JHEP 10 (2013) 042

Charmed mesons NP B907 (2016) 717 Summary

Back-up : additional plots Bottomonium PR D 87 (2013) 052004 Z + J/ψ EPJ C 75 (2015) 229 W + J/ψ JHEP 04 (2014) 172

2-7 June 2016, Krakow

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ATLAS @ LHC

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Weight : ~ 7000 tons

Inner Detector (Pixel+SCT+TRT): pT > 0.4 (0.1) GeV, |η| < 2.5 New for Run 2: Insertable B-layer (IBL) – inner-most pixel layer (r = 33 mm) and thinner beam-pipe m(µ+µ-) resolution: ~50 MeV for J/ψ ~150 MeV for ϒ Muon Spectrometr: Offline tracking: |η| < 2.7 Triggering: |η| < 2.4

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Data Taking and HF triggering

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6.76 х 1033 cm-2 s-1 5.0 х 1033 cm-2 s-1 8.2 х 1033 cm-2 s-1

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Charmonium production

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Non-prompt (from B decays) – probes open b quark production, fragmentation and B-decay kinematics FONLL, matched NLO+NLL (“massive” NLO + resummation) GM-VFNS (“massless” NLO + mass-dependent terms)

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Charmonium production

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Non-prompt (from B decays) – probes open b quark production, fragmentation and B-decay kinematics FONLL, matched NLO+NLL (“massive” NLO + resummation) GM-VFNS (“massless” NLO + mass-dependent terms)

NRQCD: Color Singlet (CS) and Color Octet (CO)

  • terms. Long-distance matrix elements (LDME)

determined from experimental data. Color Singlet Model (CSM) – only CS diagrams. Color Evaporation Model (CEM) – only one LDME.

Prompt (not from B decays) – probes specific mechanisms of QQ̄ system production and transformation to a meson

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Charmonium production

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Non-prompt (from B decays) – probes open b quark production, fragmentation and B-decay kinematics FONLL, matched NLO+NLL (“massive” NLO + resummation) GM-VFNS (“massless” NLO + mass-dependent terms)

NRQCD: Color Singlet (CS) and Color Octet (CO)

  • terms. Long-distance matrix elements (LDME)

determined from experimental data. Color Singlet Model (CSM) – only CS diagrams. Color Evaporation Model (CEM) – only one LDME.

Prompt (not from B decays) – probes specific mechanisms of QQ̄ system production and transformation to a meson

Ψ(2S) – nearly feed-down free J/ψ – feed-downs ~35%

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Charmonium production: J/ψ, 13 TeV

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ATLAS-CONF-2015-030

~70 000 di-muons

Pseudo-proper decay time:

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Charmonium production: J/ψ, 13 TeV

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rises from ~25% till ~60% Non-Prompt Fraction No strong dependence from |y| range No sizeable differences between 7 and 13 TeV results Larger than at smaller pp and pp̅ energies

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Charmonium production: J/ψ, ψ(2S), χс, 7-8 TeV

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ψ(2S), JHEP 09 (2014) 079 χc1/2, JHEP 07 (2014) 154 J/ψ and ψ(2S), EPJ C76 (2016) 283

J/ψ, ψ(2S) → μ+μ- ψ(2S), X(3872) → J/Ψ π+π- χc1/2 → J/ψ γ

ψ(2S) and X(3872), ATLAS-CONF-2016-0XX

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J/ψ (→μ+μ-), 8 TeV, non-prompt diff. x-sections

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  • generally, reasonable description by FONLL
  • predictions are harder than data
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ψ(2S) → J/ψ (→μ+μ-)π+π-, non-prompt diff. x-sections

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  • generally, reasonable description by FONLL and GM-VFNS

predictions are harder than data

  • NLO with “wrong” (FONLL) fragmentation is even harder
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χс1/2 → J/ψ (→μ+μ-) γ, non-prompt diff. x-sections

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FONLL describes reasonably (somewhat harder)

ATLAS, χc1/2, JHEP 07 (2014) 154

Absolute χс1/2 cross sections are measured

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J/ψ, 8 TeV, prompt diff. x-sections

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NLO NRQCD (Y.Q. Ma et al.) is generally o.k.

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ψ(2S) and χc1/2, prompt diff. x-sections

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kT –factorization predictions (CS) (Baranov et al.) need to be re-tuned

  • NLO NRQCD is generally o.k.
  • CS is too low even at NNLO*
  • CEM is somewhat too hard
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χс1/2 → J/ψ (→μ+μ-) γ, ratios for prompt diff. x-sections

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reasonable description by NLO NRQCD LO CSM does not describe good agreement between LHC experiments

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X(3872), 8 TeV, prompt/non-prompt diff. x-sections

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NLO NRQCD (C. Meng et al.), χc1(2P) + D0D ̅ *0, produced dominantly via χc1(2P) , tuned to CMS, is generally o.k.

ATLAS-CONF-2016-0XX

FONLL, rescaled from ψ(2S), with f(B→X(3872)→J/ψπ+π-)=(1.9±0.8)×10-4 (Artoisenet&Braaten with CDF data) is too high, too hard

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X(3872), 8 TeV, indication of enhanced Bc contribution

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Non-prompt X(3872) production suggests enhanced Bc contribution ATLAS-CONF-2016-0XX Short-lived component ̴ a/pT

2 (recombination)

τlong-lived = 1.45 ± 0.05 ps τshort-lived = 0.40 ± 0.05 ps

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Beauty meson production: B+→J/ψK+, 13 TeV

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ATLAS-CONF-2015-064

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Beauty meson production: B+→J/ψK+, 7 TeV

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FONLL provides reasonable description although with large theor. uncertainties Central predictions are somewhat harder The predictions are normalized to f(b→B+) = 40.1 ± 1.3% [PDG]

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Strangeness suppression in b fragmentation: fs /fd , 7 TeV

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pQCD, X. Liu et al.

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No sizeable pT and η dependence Good agreement with other measurements

Strangeness suppression in b fragmentation: fs /fd , 7 TeV

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Charmed meson production: D*±, D±, Ds

±, 7 TeV

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D*+ → D0 π+ → (K- π+) π+ (+c.c.) D+ → K- π+ π+ (+c.c.) Ds

+ → φ π+ → (K- K+) π+ (+c.c.)

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D meson visible x-sections

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low-pT: 3.5 – 20 GeV high-pT: 20 - 100 GeV POWHEG+PYTHIA/HERWIG – matched NLO+LL (developed from “massive” NLO) MC@NLO (+HERWIG) – matched NLO+LL (developed from “massive” NLO) FONLL – matched NLO+NLL (developed from “massive” NLO) GM-VFNS – developed from “massless” NLO, consider explicitly flavour excitation diagrams, consider fragmentation of light quarks and gluons to D mesons

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D*± signals and visible x-sections

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DATA: POWHEG+PYTHIA: FONLL:

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Summary

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X(3872) production, Prompt: NLO NRQCD (χc1(2P) dominance) agrees Non-Prompt: FONLL is too high (large Br uncert.) an indication of enhanced Bc

+ contribution

Beauty meson x-sections: FONLL generally agree (somewhat harder, like for charmonium) Charmed meson x-sections: GM-VFNS agree in shape and norm.,

FONLL and POWHEG below the data, agree within large theor. uncert.,

MC@NLO shows the worst shape description More results at 13 TeV with up to 25 fb-1 by the end of 2016, and with ~100 fb-1 by Meson 2018 Charmonium production: non-prompt fractions are similar at 7 TeV and 13 TeV, larger than those at smaller pp and pp̅ energies Beauty and charmed meson productions: strangeness suppression is ~0.25 in both beauty and charm fragmentation Charmonium x-sections, Non-Prompt: FONLL and GM-VFNS agree Prompt: only NLO NRQCD generally agree

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Back-up Slides

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LHC

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Run 1 25 fb-1 Run 2 100 fb-1 Run 3 300 fb-1 Run 4 HL-LHC 3000 fb-1 7-8 TeV 13 TeV

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Inner Detector and Muon Spectrometer

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Minimum-Bias Trigger

At least one hit above threshold in the Minimum-Bias Trigger Scintillators at each end of the detector Efficiency is ~100% for events with at least 2 tracks passing beam-spot region MBTS trigger allow us to measure D-mesons production cross-sections without uncertainty originating from trigger efficiency

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The trigger is heavily prescaled with luminosity increase

MinBias Trigger Scintillator at z=±3.56 m

  • n LAr cryostat; 2 rings with 8 sector in azimuth

2.09<|η|<2.82, 2.82<|η|<3.84

Number of tracks

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ψ(2S) → J/ψ (→μ+μ-)π+π-

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To separate prompt and non-prompt (from B decays) production pseudo-proper lifetime is used

JHEP 09 (2014) 079 ~ 200 000 ψ(2S) mesons

  • contributes to inclusive J/ψ

x-sections

  • free from feed-downs of

heavier charmonium states

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χс1/2 → J/ψ (→μ+μ-) γ

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JHEP 07 (2014) 154

To separate prompt and non-prompt (from B decays) production pseudo-proper lifetime is used

  • nly converted photons
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ψ(2S) → J/ψ (→μ+μ-)π+π-, prompt diff. x-sections

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  • NLO NRQCD is generally o.k.
  • CS is too low even at NNLO*
  • CEM is somewhat too hard
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Beauty hadron production: B+→J/ψK+, 13 TeV

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flavor creation (gg → QQ̄ , qq̄ → QQ̄) gluon splitting (g → QQ̄) flavor excitation (gQ → gQ, qQ → qQ)

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Bottomonium production, 7 TeV

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PRD 87 (2013) 052004

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Bottomonium production, 7 TeV

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PRD 87 (2013) 052004

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Z + J/ψ production (1st obs.)

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ATLAS, Z + J/Ψ, arXiv:1412.6428

Prompt component probes mechanisms of cc̄ system production and transformation to a meson at high scale; potentially sensitive to Double Parton Scattering (DPS)

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Z + J/ψ (→μ+μ-), Δφ distributions and DPS

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Prompt: Non prompt: ATLAS (W + 2 jets) ATLAS (Z + J/ψ)

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Z + J/ψ (→μ+μ-), integrated and diff. cross sections

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Predictions below data

NRQCD: Mao et al. CSM: Gong et al.

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W + J/ψ (→μ+μ-)

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ATLAS, W + J/Ψ, JHEP 04 (2014), 172

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W + J/ψ (→μ+μ-), Δφ distr. and rates w.r.t. inclusive W

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DPS:

NLO CO: Mao et al. LO CS: Lansberg et al.