High-energy photon collisions at the LHC -- Summary --

High-energy photon collisions at the LHC

-- Summary --Michael Klasen (LPSC Grenoble)

April 25, 2008

High-energy photon collisions at the LHC

-- Summary --Michael Klasen (LPSC Grenoble)

April 25, 2008

April 25, 2008 Michael Klasen (LPSC Grenoble) 3

Introduction

Higgs production (K. Piotrzkowski):h0: Diffractive > photoproductionH/: Drell-Yan > photoproduction

SUSY particle production: ll, J. Ohnemus, T.F. Walsh, P.M. Zerwas, PLB 328 (1994) 369

~ ~ ~ ~

(M. Herquet)


Photon physics at LEPTwo phases (M. Przybycien):

LEP-I : s = 91 GeVLEP-II: s = 161-209 GeV

Untagged events:tot

(L3 = OPAL):Soft IP & IR, but no hard IPInclusive jets (L3 OPAL): OPAL agrees with NLO (KKK)Dijets (OPAL):Separate D, SR, and DR with x

Charged hadrons (L3 OPAL): Harder pT-spectrum than in p

Single-tagged events:F

2: QED, hadronic, charm, sAlt. power counting (J. Hejbal)

Double-tagged events:F*

2: QED, hadronic, Fe2,tot

**

Albino, MK, Söldner-Rembold, PRL 89 (2002) 122004

PDG, JPG 33 (2006) 1


Photon physics at HERAPrecise experimental results (T. Schörner-Sardenius):

Hard scattering: S=½ quark vs. S=1 gluon exchange (cos )Photon structure: From LAC / GRV to AFG / CJK (xp <> 0.1)Proton structure: Up to 60% from gluon initial state(x>0.8)

Large theoretical errors (J. Chyla):Choice of ren./fact. scheme: DIS/MS; massive/ZM-VFNS/GM-VFNSChoice of ren./fact. scale: F; saddle pointNeed direct contribution at NNLO (Hard ! Resummation, MC@NLO)Prompt photons at Tevatron: Need larger pT !

Transition from real to virtual photons:Forward jets, particles at HERA: BFKL vs. DGLAP evolutionLHC: Elastic events. Low-mass exchanges possible ? Forward n !


Photon physics at ILC (1)Photons collider (V. Telnov):

Bremsstrahlung: Low E, LCompton scatt.: High E, LAdjust EL, Pe,L, bL, X-angleMeasure L ( ll, e e)

Physics (A. de Roeck): h,A,H bbe e eAnomalous gWtb

Detector requir.s (J. Gronberg):Higgs: E/E3%(jet), 5m(b)SUSY: HermiticityPLC: Affects beam pipe, endcap

Detector concepts:US: SiD (silicon tracker)Asia/EU: GLD/LDC ILD (TPC)

_

~~ ~~


Photon physics at ILC (2) at LHC

IP » , needs S2

Sarycheva, Ovyn - ” - ? Gronberg, Schul ? ? v.Manteuffel, Pierzchala Machado Insufficient s ? Low rate g ? Favereau Godbole ? ? ? Kumar, Nystrand


Photon physics at ILC (3)Higgs mass:

m ~ 100 MeV / 1 year running ~ ee,pp/2Partial width ():

2-7% in bb channel (needs h bb from ee)15% in ee

3-10% in WW, ZZ channel (needs BR from ee) ~ ee

Determination of the phase of the h amplitude:3-10% in WW, ZZ channel Unique ?

CP analysis:h ZZ, WW angular analysis More poss.,h tt interference w/ QED BG, l charge asymmetries clean testsLinear polarization

Rare decay modes:h !, h Z ? Difficult

Discovery reach for H, A:Up to 0.8 see for see ~ 800 GeV s/2-50 GeV


Photon physics at hadron collidersAdvantages (M. Strikman, Phys. Rep. 458 (2008) 1):

RHIC, Tevatron and LHC existCan reach s 486 GeV in O+O (400 GeV at ILC)Not only , but also p / A collisions

Disadvantages:Much less bremsstrahlung (mp » me) compensate with ZNot only , but also IP interactions el. weak final statesUncertain photon flux monitor luminosity ( ll)

Luminosity monitor: llCMS (J. Hollar): pT > 3 (6) GeV for (ee), || > 2.9 (2.7) (low L)Krakow-Paris (W. Krasny): pT > 0.2 (6) GeV, || > 3.1

FP 220 / FP 420 acceptance (X. Rouby):Proton transport in beamline: HECTOR, MAD-XFP 420: 20 GeV < E < 120 GeV (E = 2…1 GeV)FP 220: 120 GeV < E < 900 GeV (E = ?)Q2 = 0.01 … 1 GeV2 (Q2 = 0.02 … 0.06 GeV2)


Photon spectra at hadron collidersUPC (C. Güclü, G. Baur):

b > R1+R2Coherent rad. by nucleus

Strong fields: Z1Z2/137 » 1Vibration of nucleiGiant dipole resonanceLarge soft cross sectionsee pair production e capture beam lossIon beam = straight lineIntegrate over bSemiclassical/Glauber phase

A/A interference


Photon physics at RHICTypical process:

Low multiplicity:1st vertex, 2 tracks, low pT

Nuclear breakup:Forward neutrons

STAR (B. Grube):: s-channel hel. conserv.ee: LO QED ? (Z=0.6 !)

PHENIX (S. White): J/ ee


Photon physics at TevatronMotivation (J. Pinfold):

Luminosity measurementCalibrate FP 420Search for c, odderon, h0, …

CDF detector components:Miniplug calorimeter:3.5 < || < 5.5Beam shower counters:5.5 < || < 6Roman pots not used !

Run-II data (532 pb-1/1.48 fb-1):

ee: 16 events (QED)IP IP : 3 ev. (2 , 1 00 ?) , IP J/’ / :334 / 145 events


ATLAS, CMS & ALICE forward detectors

ATLAS (Giacobbe, de Roeck):

L Ar forward: 3.1<||<4.9LUCID: 5.6<||<6 (?)ALFA: Lpp at 2-3%, tot

FP420: 0.002 < x1,2 < 0.02

ALICE (R. Schicker):Hadronic central: ||<0.9Muon spectr.: 2.5<||<4

(?)Forward veto: 1<||<4 (5)

CMS (Grothe, de Roeck):Hadronic forward: 3<||<5CASTOR: 5.2<||<6.6TOTEM: Lpp at 1%, tot

FP420: Indispensable for

Physics (Grothe, Tasevsky):qq ll: PDFs at x1 » x2

gg jj: BFKL evolution, S2

ll: L at 4%, cal. FP420 O/IP : d/dpT

2, cal.tag. O/IP , KK: C = 1 /IP /IP h, H, A: m/m,CP


Factorisation breaking in diffractionDIS events: 10-20% diffractiveHard scale: pQCD applicableFactorisation:

Proven in DIS (Collins et al.)Broken in pp (Tevatron)

NLO DGLAP fits (A. Bruni):H1 2006 fit A, BMartin, Ryskin, WattZEUS LPS + charmSinglet well constrainedGluon badly constrained (75%)

D* and dijets in DIS and p:D*: Factorisation works in DISAlso in p ! (direct dominates)Dijets in DIS sensitive to fitsNew H1 2007 Fit Jets


Exclusive quarkonium production at LHC

CMS (V. Kumar):

Similar distribution for Ntot 500 fg/A @ small x

ALICE (J. Nystrand):

N 2108, NJ/ 105

N 400 (only ee)

22

35

2

0 )]4

,([163

V

V

eest

MxxgMdt

d


Exclusive VM production & DVCS at HERA

Exclusive VM (A.Bunyatyan):

Hard scale: Q2 or MVM2

d/dt e-b|t|: Size of VM DVCS:

Access to GPDs (B. Pire)b(Q2) = A (1 - B log Q2/2)


Inclusive quarkonium production at LHC

Color Singlet Model:Wave function: J/ eeUncanceled singularitiesLO pT-distributions failNLO corr. large (, p, pp)

Non-relativistic QCD:Effective field theory (v2)Non-pert. color octet operatorsLO pT-distributions ok (fitted)J/ polarization failsNLO corr. difficult () (KKMS)

Madonia (J.P. Lansberg):Equivalent photon approxim.Only direct photonsSimilar results for


Anomalous couplings in WW (1)Eff. Lagrang. (A.v.Manteuffel):

Precision constraints from LEPAdditional Feynman diagrams:

Choice of final states:Leptons: Clean signalJets: Large BR, full kinematics

Optimal observables:Fully differential cross sectionEvaluate covariance matrix

LHC photon flux:Tag both p’s, integrate over Q2


Anomalous couplings in WW (2)WW (T. Pierzchala):

OPAL limits LHC 1fb/10fb

WW (O. Kepka):


Anomalous couplings in WW (3)WW (O. Eboli):

LEP:

LHC:Single/an.top (J.d.Favereau):

Bg.: tt; Wj, Wb b-tag, ET

|Vtb|/Vtb = 0.1, ktu< 0.05

/


Single-W & anomalous top at HERASingle-W prod. (D. South):

Isolated e/ and missing pT

Combined H1/ZEUS analysis:H1 larger l-angle acceptanceExcess in large e data with pT

X > 25 GeV (H1, not ZEUS)Total cross sections andW polarization fractions agree with SM

Anomalous top production:


Higgs in photoproduction at LHC h (L. Sarycheva):

h bb:

h ZZ:

q hWq’ (S. Ovyn):hW lbbhW lljjhW lll3 for 100 fb-1 (m=170 GeV)No discovery channel ! m ?


Higgs in vector boson fusion at LHCVBF (D. Zeppenfeld):

Event selection:Tag forward jetsVeto central jets

Analyses:h (<140), WW (>130)5 for L = 30 fb-1

Backgrounds:qq qqWWqq qqZZ


SUSY particle production at LHC l l (J. Gronberg, N. Schul):

LM1: m0 = 60 GeVSame flavor: ee, = 2.2 fb = 0.7 fb5 discovery with 25 fb-1

Mass resolution: few GeV needs at least 100 fb-1

:LM9: m0 = 1450 GeVDifferent flavor: e, e = 3.6 fb = 0.07 fbNeeds at least 100 fb-1

Backgrounds: ee, : Acoplanarity WW: W, Wmiss

~ ~

~ ~


OutlookJet and open light/heavy quark photoproduction:

Excellent channels to constrain nuclear PDFs adapt NLO codes ?Top charge determination in g tt ? (U. Baur et al.: qq/gg tt)

Vector meson production:Very sensitive to gluon densityDetermine Pomeron slope / discover OdderonDistinguish CSM / NRQCD

Gauge boson production:Single Z: incl. = 102 SD = 104 PHP = ? DPEW pairs: Different effective Lagrangians, old limits Comparison ?

Higgs production:Hopeless in , difficult in pSUSY Higgses ?

SUSY particles:Sleptons promisingGauginos difficult Squarks (IP), gluinos (1-loop) hopeless ?R-parity violation, other BSM models ?


Instructions for Nucl. Phys. B Proc. Suppl.

8 pages per contributed talk (= 30’)12 pages per review talk (> 30’)No color figuresLatex instructions / macros will be mailed by ElsevierStrict deadline: May 31, 2008Free copy will be sent to allspeakers in fall

THANK YOU ALL FOR COMING –SEE YOU NEXT SUMMER IN BELGIUM !

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High-energy photon collisions at the LHC -- Summary --

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