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Collectivity and manifestations of minimum-bias jets in high-energy nuclear collisions Tom Trainor University of Washington ISMD 2017 Tlaxcala, Mexico Agenda What is collectivity? The two-component (soft + hard) model (TCM) p-p

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Collectivity and manifestations of minimum-bias jets in high-energy nuclear collisions

Tom Trainor

University of Washington

ISMD 2017 Tlaxcala, Mexico

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Agenda

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  • What is collectivity?
  • The two-component (soft + hard) model (TCM)
  • p-p jets, spectra, correlations and the TCM
  • p-p

π‘žπ‘’ TCM

  • p-Pb

π‘žπ‘’ TCM

  • Pb-Pb

π‘žπ‘’ TCM

  • NaΓ―ve Glauber model of p-Pb collisions
  • PYTHIA – p-p model assumptions vs reality

arXiv:1708.09412

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What is Collectivity?

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collectivity οƒž countable collection, any correlations οƒž collectivity

e.g. dijets = collective phenomenon! several mechanisms may produce correlations

  • ur task is to identify them via data analysis
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Two-component Model – TCM

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hadron production in p-p collisions near midrapidity soft component SC: projectile-nucleon dissociation hard component HC: large-angle scattered gluons β†’ dijets participant low-x gluons ο‚΅ 𝝇𝒕 ο‚΅ log(√s/10 GeV) MB jet fragments: π‡π’Š β‰ˆ a 𝝇𝒕

πŸ‘

hadron production in A-B collisions follows suite:

(noneikonal)

a = O (0.01) charge densities: soft + hard 𝑸𝒖 = (𝑢𝒒𝒃𝒔𝒖/πŸ‘) 𝒐𝒕𝑢𝑢 𝒒𝒖𝒕𝑢𝑢 + 𝑢𝒄𝒋𝒐 π’π’Šπ‘Άπ‘Ά π’’π’–π’Šπ‘Άπ‘Ά 𝑸𝒖 𝒐𝒕 = 𝒒𝒖𝒕 + π’š 𝒐𝒕 𝝃 𝒐𝒕 π’’π’–π’Šπ‘Άπ‘Ά(𝒐𝒕) extensive π‡πŸ = 𝝇𝒕 + π‡π’Š

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QCD Jets and p-p pt Spectra

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JS – jet spectra universal form

FF – fragmentation functions

hard components

p-p

PRD 89, 094011 (2014) PRD 74, 034012 (2006)



e-e

p-p

JSFF = H

UA1

JPHYSG 42, 085105 (2015)

200 GeV

200 GeV

dijet production

PYTHIA

200 GeV noneikonal

𝑸 𝒒|𝑭 𝑸 𝑭 𝑸 𝒒 :

𝑸 𝒒 =

𝑭𝒏𝒋𝒐 ∞

𝑸 𝒒|𝑭 𝑸(𝑭) dE

3 GeV 𝑸 𝑭

NSD

PRD 93, 014031(2016)

π‡π’Š β‰ˆ a 𝝇𝒕

πŸ‘

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p-p Angular Correlations – 2D Model Fits

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βˆ†π›“/ π›“π¬πŸπ  βˆ†π›“/ π›“π¬πŸπ 

two-particle correlations per-participant (per low-x gluon) model-parameter trends yt ο‚΄ yt pt β‰ˆ 0.6 GeV/c high multiplicity dijets + quad

n = 6

hard (dijets) ο‚΅ 𝝇𝒕

πŸ‘

quadrupole ο‚΅ 𝝇𝒕

πŸ’ SS 2D peak AS 1D peak

soft ο‚΅ 𝝇𝒕 LPHD

PRD 93, 014031 (2016)

S H H

no pt cuts

S H H Q

AQ0

PoS CFRNC2006, 004 (2006)

𝝇𝒕=

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π‡π’Š β‰ˆ a 𝝇𝒕

πŸ‘

p-p pt Spectrum Hard Component

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HC energy dependence lower pt cut spectrum HCs spectrum HCs HC model parameters vs nch 𝒒𝒖𝒕

β€² =

𝒒𝒖𝒕/𝝄 π’’π’–π’ŠπŸ

π’’π’–π’ŠπŸ

HC nch dependence 𝝇𝒕 = 𝒐𝒕/𝚬𝜽 SC density:

QCD jets

1 6 1

JPHYSG 44, 44, 0750 5008 08 (201 017) 7) PRD 93, 014031(2016)

(biased jet spectra)

𝝇𝒕 β‰ˆ πŸ‘ 𝝇𝒕𝑢𝑻𝑬

𝜷 𝝄

𝑸𝒖𝒕

β€² /𝒐𝒕

𝒒𝒖𝒕

β€²

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SLIDE 8

p-p π‘žπ‘’ TCM

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π’’π’–π’Š π’’π’–π’Š 𝒒𝒖

β€²

𝒒𝒖

β€²

π’’π’–π’ŠπŸ

𝒒𝒖𝒕 𝒒𝒖𝒕

β€²

𝒒𝒖𝒕

π’π’…π’Š

β€² /𝒐𝒕 = 𝝄 + π’š(𝒐𝒕)

π’š 𝒐𝒕, √s ≑ π’π’Š/𝒐𝒕 β‰ˆ 𝜷(√s) 𝝇𝒕 𝑸𝒖

β€²/π’π’…π’Š β€²

= 𝒒𝒖

β€² β‰ˆ 𝒒𝒖𝒕+π’š(𝒐𝒕) π’’π’–π’Š(𝒐𝒕) 𝝄+π’š(𝒐𝒕)

π’π’…π’Š

β€²

𝒐𝒕 𝒒𝒖

β€² β‰ˆ

𝒒𝒖𝒕 + π’š(𝒐𝒕, √s) π’’π’–π’Š(𝒐𝒕, √s)

𝝄 β‰ˆ 0.76-0.80

π’’π’–π’Š(𝒐𝒕, √s) π’’π’–π’Š 𝒐𝒕 : nch dependence, spectrum HC

direct correspondence: π’’π’–π’Š vs spectrum HC vs isolated QCD jets

(takeaway from p-p)

ALICE UA1 STAR ALICE: PLB 727, 371(2013) ALICE STAR 200 GeV

π‡πŸ= 𝝇𝒕=

arXiv:1708.09412

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SLIDE 9

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p-Pb π‘žπ‘’ TCM

𝒒𝒖

β€²

𝒒𝒖𝒕

β€²

𝒒𝒖

β€²

𝒒𝒖𝒕

π’π’…π’Š

β€² /𝒐𝒕 = 𝝄 + π’š(𝒐𝒕)𝝃(𝒐𝒕)

𝝇𝒕 = (𝑢𝒒𝒃𝒔𝒖/πŸ‘) 𝝇𝒕𝑢𝑢 (𝒐𝒕) π’š 𝒐𝒕 ≑ π‡π’Šπ‘Άπ‘Ά 𝒐𝒕 / 𝝇𝒕𝑢𝑢(𝒐𝒕) β‰ˆ 𝜷 𝝇𝒕𝑢𝑢 𝒐𝒕 𝑢𝒒𝒃𝒔𝒖/πŸ‘ = 𝜷 𝝇𝒕 / π’š 𝒐𝒕 𝑢𝒒𝒃𝒔𝒖 = 𝑢𝒄𝒋𝒐 + 𝟐 𝝃 ≑ πŸ‘π‘Άπ’„π’‹π’/𝑢𝒒𝒃𝒔𝒖

a [ π‡π’•πŸ+π’πŸ( 𝝇𝒕 βˆ’ π‡π’•πŸ)]

*

𝑸𝒖

β€²/π’π’…π’Š β€²

= 𝒒𝒖

β€² = 𝒒𝒖𝒕+π’š(𝒐𝒕)𝝃(𝒐𝒕) π’’π’–π’Šπ‘Άπ‘Ά(𝒐𝒕) 𝝄+π’š(𝒐𝒕)𝝃(𝒐𝒕)

π’π’…π’Š

β€²

𝒐𝒕 𝒒𝒖

β€² =

𝒒𝒖𝒕 + π’š(𝒐𝒕)𝝃(𝒐𝒕) π’’π’–π’Šπ‘Άπ‘Ά(𝒐𝒕) π’’π’–π’Šπ‘Άπ‘Ά(𝒐𝒕) β‰ˆ π’’π’–π’ŠπŸ no jet modification

π‡π’•πŸ β‰ˆ15

p-p value assume:

( π‡π’•πŸ, π’πŸ)

𝑸𝒖 𝒐𝒕 /𝒐𝒕=

PLB 727, 371(2013)

𝑸𝒖 𝒐𝒕 /𝒐𝒕

π’πŸ β‰ˆ 0.1

π‡πŸ= 𝝇𝒕=

arXiv:1708.09412

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SLIDE 10

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Pb-Pb π‘žπ‘’ TCM – I

π’š 𝝃 = π’šπ’’π’’ + 𝟏. πŸπŸ“πŸ‘ βˆ’ π’šπ’’π’’ Γ— 𝟐 + tanh[ 𝝃 βˆ’ πŸ‘. πŸ’ /𝟏. πŸ”] /2 𝝃(𝒐𝒕) β‰ˆ ( 𝝇𝒕/ 𝝇𝒕𝑢𝑢)𝟐/πŸ’ (𝑢𝒒𝒃𝒔𝒖/πŸ‘) π‡πŸ = 𝝇𝒕𝑢𝑢[𝟐 + π’š 𝝃 𝝃] Glauber:

  • btain from data above:

TCM for A-A yield vs centrality: π’š(𝒐𝒕) = π’š[𝝃(𝒐𝒕)] peripheral Pb-Pb follows p-p more-central Pb-Pb shows ST: jet modification

fluctuations

ST: sharp transition

PRL 106, 032301(2011)

xpp?

PRC 91, 044905(2015) PRC 86, 064902(2012)

π‡πŸ 𝝇𝒕= 𝝇𝒕=

ST: PRC 86, 064902(2012)

xpp?

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SLIDE 11

11

Pb-Pb π‘žπ‘’ TCM – II

𝑸𝒖

β€²/π’π’…π’Š β€²

= 𝒒𝒖

β€² = 𝒒𝒖𝒕+π’š(𝒐𝒕)𝝃(𝒐𝒕) π’’π’–π’Šπ‘Άπ‘Ά(𝒐𝒕) 𝝄+π’š(𝒐𝒕)𝝃(𝒐𝒕)

π’’π’–π’Šπ‘Άπ‘Ά(𝒐𝒕) given Glauber 𝝃(𝒐𝒕) solve for: given π’š(𝒐𝒕) solve for: π’š 𝒐𝒕 π’’π’–π’Šπ‘Άπ‘Ά 𝒐𝒕 β‰ˆ π‘Έπ’–π’Šπ‘Άπ‘Ά/𝒐𝒕𝑢𝑢 new information from Pb-Pb: π’’π’–π’Šπ‘Άπ‘Ά(𝒐𝒕) follows p-p trend for peripheral, falls to saturation value for central minimum is 73% of maximum

π’’π’–π’ŠπŸ

𝒒𝒖

β€²

𝒒𝒖𝒕

β€²

PLB 727, 371(2013)

𝒒′ 𝒒′ 𝒒′

π’’π’–π’Šπ‘Άπ‘Ά(𝒐𝒕)

xpp?

arXiv:1708.09412

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Lessons from

π‘žπ‘’ Data

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  • p-p

π’’π’–π’Š(𝒐𝒕, √s) trends agree with spectrum HC and MB dijets

  • p-p dijet production is noneikonal, centrality not relevant
  • p-Pb

𝒒𝒖(𝒐𝒕) establishes factorization of A-B Glauber and N-N noneikonal

  • p-Pb

𝒒𝒖 data confirm MB dijets dominate 𝒒𝒖(𝒐𝒕) trends

  • Pb-Pb

𝒒𝒖 data confirm that naΓ―ve Glauber dominates A-A collisions, but peripheral A-A collisions follow p-p trends

  • Pb-Pb

π’’π’–π’Šπ‘Άπ‘Ά 𝒐𝒕 trend confirms jets are modified above ST

  • Jets still dominate structure in more-central Pb-Pb collisions

three successive collision systems

arXiv:1708.09412

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NaΓ―ve Glauber Model for p-Pb

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black points derived from nch, Npart, Nbin, b Glauber values in

𝒒𝒖

β€²

𝒒𝒖𝒕

β€²

𝒆𝑸/π’†π’π’š β†’ (𝟐/π‰πŸ) 𝒆𝝉/π’†π’π’š

assumes: 𝒆𝑸/π’†π’π’š

β€œ[nch] at mid-rapidity scales linearly with [Npart]”

𝑢𝒒𝒃𝒔𝒖 = 𝑢𝒄𝒋𝒐 + 𝟐 𝐣𝐨 π’’βˆ’π

PLB 727, 371(2013) PLB 727, 371(2013)

𝟐 βˆ’ 𝝉 π‰πŸ

𝝉 π‰πŸ = 𝒄 π’„πŸ πŸ‘ ο‚΄ 100

uncertainty?

β†’x(nch)

β‰ˆTCM

b0 β‰ˆ 8 fm

π‡πŸ

π’’π’–π’ŠπŸ=1.3 GeV/c

nx ?

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PLB 727, 371(2013)

PYTHIA (and Other Monte Carlos)

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MPI = multiple parton interactions π’π’…π’Š ∝ 𝒐𝑡𝑸𝑱 𝒐𝑡𝑸𝑱(𝒄) depends on centrality eikonal model 𝒒𝒖(π’π’…π’Š) trend requires color reconnection (CR) no jet spectrum cutoff π’’πŸ β†’ πŸ‘ GeV

arXiv: 1706.02166

CR

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SLIDE 15

PLB 727, 371(2013)

PYTHIA (and Other Monte Carlos)

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eikonal CR (HCο‚΄3)

𝒒𝒖𝒕

β€²

MPI = multiple parton interactions π’π’…π’Š ∝ 𝒐𝑡𝑸𝑱 𝒐𝑡𝑸𝑱(𝒄) depends on centrality eikonal model 𝒒𝒖(π’π’…π’Š) trend requires color reconnection (CR) no jet spectrum cutoff π’’πŸ β†’ πŸ‘ GeV those assumptions conflict with MB dijets and the p-p TCM see also HIJING, AMPT

arXiv: 1706.02166

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Conclusions

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  • TCM provides accurate, comprehensive description
  • Soft component S(yt) is universal:

𝝇𝒕 ~ low-x gluons

  • Jets dominate

π’’π’–π’Š(𝒐𝒕, √s) structure in all systems

  • Centrality not relevant for p-p collisions (noneikonal)
  • A-B systems evolve from isolated N-N to Glauber
  • NaΓ―ve Glauber model applied to p-A system fails
  • p-p TCM is opposite to PYTHIA basic assumptions
  • A-B β€œcollectivity” is jet manifestations, not flows