LHC Results Support RENORM Predictions of Diffraction · PPP Pomeron-proton x-section e s o s /2 (...
Transcript of LHC Results Support RENORM Predictions of Diffraction · PPP Pomeron-proton x-section e s o s /2 (...
LHC Results Support RENORM
Predictions of Diffraction
1 MIAMI 2014 LHC Results Support RENORM Predictions of Diffraction K.Goulianos
Konstantin Goulianos
RENORM
http://physics.rockefeller.edu/dino/my.html
Basic and combined diffractive
processes CONTENTS
Diffraction
SD1 ppp-gap-X
SD2 pX-gap-p Single Diffraction / Single Dissociation
DD ppX-gap-X Double Diffraction / Double Dissociation
CD/DPE ppgap-X-gap Cenral Diffraction / Double Pomeron Exchange
Renormalizationunitarization
RENORM model
Triple-Pomeron coupling
Total Cross Section
RENORM predictions Confirmed
References
Talks Diffraction 2014 K. Goulianos, in https://agenda.infn.it/conferenceOtherViews.py?view=nicecompact&confId=7520#20140915
Low-X 2014 http://indico.cern.ch/event/323898/session/2/contribution/23
Miami 2013 https://cgc.physics.miami.edu/Miami2013/Goulianos.pdf
DATA:
CMS PAS http://cds.cern.ch/record/1547898/files/FSQ-12-005-pas.pdf
CMS paper (to be released soon) “Measurement of diffractive dissotiation cross sections in pp collisions at √s =& TeV”
2 MIAMI 2014 LHC Results Support RENORM Predictions of Diffraction K.Goulianos
Basic and combined diffractive
processes
Basic and combined
diffractive processes
4-gap diffractive process-Snowmass 2001- http://arxiv.org/pdf/hep-ph/0110240
gap
SD
DD
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KG-PLB 358, 379 (1995)
Regge theory – values of so & gPPP?
Parameters:
s0, s0' and g(t)
set s0‘ = s0 (universal IP )
determine s0 and gPPP – how?
a(t)=a(0)+a′t a(0)=1+e
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A complicatiion… Unitarity! A complication … Unitarity!
ssd grows faster than st as s increases *
unitarity violation at high s
(similarly for partial x-sections in impact parameter space)
the unitarity limit is already reached at √s ~ 2 TeV !
need unitarization
* similarly for (dsel/dt)t=0 w.r.t. st, but this is handled differently in RENORM
RENORM predictions for diffraction at LHC confirmed
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Factor of ~8 (~5)
suppression at
√s = 1800 (540) GeV
diffractive x-section suppressed relative
to Regge prediction as √s increases
see KG, PLB 358, 379 (1995)
1800 G
eV
540 G
eV
M
x,t p
p
p’
√s=22 GeV
RENORMALIZATION
FACTORIZATION BREAKING IN
SOFT DIFFRACTION
C
D
F
Interpret flux as gap
formation probability
that saturates when it
reaches unity
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Gap probability (re)normalize to unity
Single diffraction renormalized - 1
yy
yt ,2 independent variables:
t
color
factor 17.0
)0(
)(
ppIP
IPIPIP tg
gap probability subenergy x-section
KG CORFU-2001: http://arxiv.org/abs/hep-ph/0203141
y
o
yt
p eetFCyddt
d
eae ss 22
2
)(
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Single diffraction renormalized - 2
17.0)0(
)(
ppIP
IPIPIP tg
color
factor
Experimentally: KG&JM, PRD 59 (114017) 1999
QCD:
104.0,02.017.0
e
pIP
IPIPIPg
18.03
125.0
8
175.0
121f
1
1f
2
Q
NN c
q
c
g
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Single diffraction renormalized - 3
constsb
ss
sd
ln
ln~s
set to unity
determines so
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M2 distribution: data M2 distribution: data
KG&JM, PRD 59 (1999) 114017
e
factorization breaks down to ensure M2 scaling
ε12
2ε
2 )(M
s
dM
dσ
Regge
1
Independent of s over 6 orders of magnitude in M2
M2 scaling
ds/dM2|t=-0.05 ~ independent of s over 6 orders of magnitude!
data
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Scale s0 and PPP coupling
Two free parameters: so and gPPP
Obtain product gPPP•soe / 2 from sSD
Renormalized Pomeron flux determines so
Get unique solution for gPPP
Pomeron-proton x-section
eos
)(s /2
o tgPPPe
Pomeron flux: interpret as gap probability
set to unity: determines gPPP and s0 KG, PLB 358 (1995) 379
)sξ()ξ,t(fdtdξ
σdIP/pIP/p
SD
2
s
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Saturation at low Q2 and small-x
figure from a talk by Edmond Iancu
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DD at CDF
renormalized
gap probability x-section
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SDD at CDF
Excellent agreement
between data and MBR
(MinBiasRockefeller) MC
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CD/DPE at CDF
Excellent agreement
between data and MBR
low and high masses are
correctly implemented
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Difractive x-sections
a1=0.9, a2=0.1, b1=4.6 GeV-2, b2=0.6 GeV-2, s′=s e-y, =0.17,
2(0)=s0, s0=1 GeV2, s0=2.82 mb or 7.25 GeV-2
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Total, elastic, and inelastic x-sections
GeV2
KG Moriond 2011, arXiv:1105.1916
selp±p =stot×(sel/stot), with sel/stot from CMG
small extrapol. from 1.8 to 7 and up to 50 TeV )
CMG
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The total x-section
√sF=22 GeV
98 ± 8 mb at 7 TeV 109 ±12 mb at 14 TeV
Main error
from s0
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Reduce the uncertainty in s0
glue-ball-like object “superball”
mass 1.9 GeV ms2= 3.7 GeV
agrees with RENORM so=3.7
Error in s0 can be reduced by
factor ~4 from a fit to these data!
reduces error in st.
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TOTEM vs PYTHIA8-MBR
sinrl7 TeV= 72.9 ±1.5 mb sinrl
8 TeV= 74.7 ±1.7 mb TOTEM, G. Latino talk at MPI@LHC, CERN 2012
MBR: 71.1±5 mb
superball ± 1.2 mb
RENORM: 72.3±1.2 mb RENORM: 71.1±1.2 mb
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SD,DD extrapolations to x ≤ 0.05 vs MC models C
MS
data
best
described b
y P
YT
HIA
8-M
BR
Central yellow-filled box is the data region (see left figure)
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pT distr’s of MCs vs Pythia8 tuned to MBR
COLUMNS
Mass Regions
Low 5.5<MX<10 GeV
Med. 32<MX<56 GeV
High 176<MX<316 GeV
ROWS
MC Models
PYTHIA8-MBR
PYTHIA8-4C
PYTHIA8-D6C
PHOJET
QGSJET-II-03(LHC)
QGSJET-04(LHC)
EPOS-LHC CONCLUSION
PYTHIA8-MBR agrees
best with reference
model and can be
trusted to be used in
extrapolating to the
unmeasured regions.
Pythia8 tuned to MBR
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Charged mult’s vs MC model – 3 mass regions Pythia8 parameters tuned to reproduce
multiplicities of modified gamma distribution
KG, PLB 193, 151 (1987)
Mass Regions
Low 5.5<MX<10 GeV
Med. 32<MX<56 GeV
High 176<MX<316 GeV
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Pythia8-MBR hadronization tune
24
1+arkprobPickQu
arkprobPickQu=qP
1
1
+arkprobPickQu=gP
PYTHIA8
default
sPp(s) expected from Regge phenomenology for s
0=1 GeV2 and DL t-dependence.
Red line:-best fit to multiplicity distributions. (in bins of Mx, fits to higher tails only, default pT spectra)
good description of low multiplicity tails
nave=σQCD
σIPp
R. Ciesielski, “Status of diffractive models”, CTEQ Workshop 2013
Diffraction: tune SigmaPomP Diffraction: QuarkNorm/Power parameter
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SD and DD x-sections vs theory
KG*: after extrapolation into low x from the measured CMS data using MBR model
Includes ND background
KG* KG*
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Monte Carlo algorithm - nesting
y'c
Profile of a pp inelastic collision
y‘ < y'min
hadronize
y′ > y'min
generate central gap
repeat until y' < y'min
ln s′
=y′
evolve every cluster similarly
gap gap no gap
final state
of MC w/no-gaps
t
gap gap
t t t1 t2
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SUMMARY
Introduction
Diffractive cross sections:
basic: SD1,SD2, DD, CD (DPE)
combined: multigap x-sections
ND no diffractive gaps:
this is the only final state to be tuned
Monte Carlo strategy for the LHC – “nesting”
derived from ND
and QCD color factors
Thank you for your attention! MIAMI 2014 LHC Results Support RENORM Predictions of Diffraction K.Goulanos 27
Special thanks to Robert A. Ciesielski, my collaborator in the PYTHIA8-MBR project
Warm thanks to my CDF and CMS colleagues, and to to Office of Science of DOE
28 MIAMI 2014 LHC Results Support RENORM Predictions of Diffraction K.Gouliano
http://physics.rockefeller.edu/dino/my.html