K.Eggert/CERN

TOTEM PhysicsTOTEM Physics tot

elastic scattering

diffraction (together with CMS)

Karsten Eggert

CERN, PH Department

on behalf of the

TOTEM Collaborationhttp://totem.web.cern.ch/Totem/

Politecnico di Bari and Sezione INFN

Bari, Italy

Case Western Reserve University

Cleveland, Ohio,USA

Institut für Luft- und Kältetechnik, Dresden, Germany

CERN, Geneva, Switzerland

Università di Genova and Sezione INFN Genova, Italy

University of Helsinki and HIP, Helsinki, Finland

Academy of Sciences,Praha, Czech Republic

Penn State University

University Park, USA

Brunel University, Uxbridge, UK

XI th Int. Conf. on Elastic and Diffractive Scattering, Blois, France, May 2005

TOTEM TDR is fully approved by the LHCC and the Research Board

K.Eggert/CERN

TOTEM Physics

Total cross-section with a precision of 1%

Elastic pp scattering in the range 10 -3 < t = (p )2 < 10 GeV2

Particle and energy flow in the forward direction

Measurement of leading particles

Diffractive phenomena with high cross-sections

Different running scenarios (* = 1540, 170, 18, 0.5 m)

K.Eggert/CERN

• Current models predict for

14 TeV: 90 – 130 mb• Aim of TOTEM: ~ 1%

accuracy

Luminosity independent method:

Total p-p Cross-SectionTotal p-p Cross-Section

COMPETE Collaboration:

inelel

ttot NN

dtdN

0

2

)/(

1

16

02

2

1

16L

t

tot dt

dN

inelasticelastictot NN L

Optical Theorem

COMPETE Collaboration fits all available hadronic data and predicts at LHC:

mb 1.41.2

2.1 5.111 tot

[PRL 89 201801 (2002)]

K.Eggert/CERN

T1:3.1 << 4.7

T2: 5.3 < < 6.5

T1 T2 CASTOR (CMS)

RP1 (147 m) RP2 (180 m) RP3 (220 m)

Experimental apparatus

K.Eggert/CERN

T1 and T2 TelescopesT1 and T2 Telescopes

~3 m

T1: Cathode Strip Chambers

Compass APV hybrids400 mmCastor Calorimeter (CMS)

Vacuum ChamberT2: GEMs

2004 Test Beam in X5

<IP5

(see talk of G. Ruggiero)

K.Eggert/CERN

Roman Pot station with two units 4 m apart

Roman Pot unit

-Vertical and horizontal pots mounted as close as possible-BPM fixed to the structure gives precise position of the beam-Final prototype at the end of 2005

BPMBPM

K.Eggert/CERN

Planar technology: Testbeam 40 m dead area

Detector 1Detector 1 Detector 2Detector 2

Edgeless Silicon Detectors for the RPsEdgeless Silicon Detectors for the RPs

active edges(“planar/3D”)

planar technology CTS(Curr. Termin. Struct.)

50

m d

ead

are

a

10

m d

ead

are

a

66 m pitch

Add here photo of RP

Active edges: X-ray measurement

m

Sig

nal

[a.

u.]

5m deadarea

Strip 1 Strip 2

K.Eggert/CERN

Running ScenariosRunning Scenarios

ScenarioScenarioPhysics:Physics:

11low |t| elastic,low |t| elastic,

tot tot ,,

min. bias, min. bias, soft diffractionsoft diffraction

22large |t| large |t| elasticelastic

33diffractiondiffraction

44hard hard

diffractiondiffraction

(under study)(under study)

** [m] [m] 15401540 1818 15401540 170170

N of bunchesN of bunches 4343 28082808 156156 28082808

N of part. per bunchN of part. per bunch 0.3 x 100.3 x 101111 1.15 x 101.15 x 101111 (0.6 - 1.15) x (0.6 - 1.15) x 10101111

1.15 x 101.15 x 101111

Half crossing angleHalf crossing angle

[[rad]rad]

00 160160 00 150150

Transv. norm. emitt. Transv. norm. emitt. [[m rad]m rad]

11 3.753.75 1 - 3.751 - 3.75 3.753.75

RMS beam size at RMS beam size at IP [IP [m]m]

454454 9595 454 - 880454 - 880 270270

RMS beam diverg. RMS beam diverg.

[[rad]rad]

0.290.29 5.285.28 0.29 - 0.570.29 - 0.57 1.71.7

Peak luminosityPeak luminosity

[cm[cm-2-2 s s-1-1]]

1.6 x 101.6 x 102828 3.6 x 103.6 x 103232 2.4 x 102.4 x 102929 ~ 0.5 10~ 0.5 103232

K.Eggert/CERN

TOTEM Optics ConditionsTOTEM Optics Conditions

High- optics for precise measurement of the scattering angle *) = / * ~ 0.3 rad

As a consequence large beam size * = * ~ 0.4 mm

Reduced number of bunches ( 43 and 156 ) to avoid interactions further downstream

Parallel-to-point focusing ( v=0) :

Trajectories of proton scattered at the same angle but at different vertex locations

LTOTEM ~ 1028 cm-2 s –1

TOTEM needs special/independent short runs at high-**1540m1540mand and lowlowScattering angles of a few rad

y = Ly y*+ vy y* L = ()1/2 sin (s)

x = Lx x *+vx x*+Dx v = ()1/2 cos (s)

Maximize L and minimize v

K.Eggert/CERN

v= ()1/2 cos (s)

L = ()1/2 sin (s)

High optics ( 1540 m ): lattice functions

DxvLx

yvLy

xxx

yy y

**

**

L (m)

v

Parallel to point focusing in both projections

K.Eggert/CERN

Elastic Scattering* = 1540 m

acceptance

K.Eggert/CERN

Elastic Scattering: ResolutionElastic Scattering: Resolutiont-resolution (2-arm measurement) -resolution (1-arm measurement)

Test collinearity of particles in the 2 arms Background reduction.

correlation in DPE

K.Eggert/CERN

Elastic Cross section (t=0)

Uncertainty Fit error

Beam divergence 10% -0.05%Energy offset 0.1% -0.25% 0.05% -0.1%Beam/ detector offset 100m -0.32/-0.41 % 20m -0.06/-0.08 %Crossing angle 0.2rad -0.08/-0.1%

Theoretical uncertainty (model dependent) ~ 0.5%

Beam offset (20 m)

Energy offset (0.1%)

Beam offset (100 m)

Statistical error

L dt=4 1032 cm-2

tmax = 0.1 GeV2

K.Eggert/CERN

Extrapolation uncertainty due to Coulomb interference

Change of the slope BCoulomb interference

Extrapolation to t=0 model dependent

Error < 0.5 % d/dt ~ exp( -Bt)

K.Eggert/CERN

Accuracy of tot

(inel.~80mb, el.~30mb)

(mb)(mb) Double Double armarm

Single armSingle arm After ExtrapolationAfter Extrapolation

Minimum biasMinimum bias 5858 0.30.3 0.060.06 0.060.06

Single diffractiveSingle diffractive 1414 -- 2.52.5 0.60.6

Double diffractiveDouble diffractive 77 2.82.8 0.30.3 0.10.1

Double PomeronDouble Pomeron 11 -- -- 0.020.02

Elastic ScatteringElastic Scattering 3030 -- -- 0.10.1

Trigger Losses (mb)

Acceptance

Vertex extrapolation

01.0005.00.008 22

tot

tot

simulated

extrapolated

detected

Inelastic error t=0 extrapol. error

K.Eggert/CERN

Try to reach the Coulomb region and measure interference:

• move the detectors closer to the beam than 10 + 0.5 mm• run at lower energy √s < 14 TeV

Possibilities of Possibilities of measurement measurement

K.Eggert/CERN

Elastic Scattering Cross-SectionElastic Scattering Cross-Section

diffractive structure

Photon - Pomeron interference

pQCD

* = 1540 m

L = 1.6 x 1028 cm-2 s-1

(1)

*=18 m

L = 3.6 x 1032 cm-2 s-1

(2)

pp 14 TeVBSW model

Multigluon (“Pomeron”) exchange e– B |t|

-t [GeV2]

t p2 2

d/ d

t [m

b / G

e V2 ]

~1 day(1) (2)

wide range of predictions

104 per bin

of 10-3 GeV2

K.Eggert/CERN

> 90 % of all diffractive protons are detected10 million min. bias events, including all diffractive processes, in a 1 day run with * = 1540 m

CMS+TOTEM: largest acceptance detector ever built at a hadron collider

Ro

ma

n P

ots

TOTEM+CMS

T1,T2 T1,T2

Ro

ma

n P

ots

Charged particles

Energyflux

CMS + TOTEM: AcceptanceCMS + TOTEM: AcceptancedNdN

chch/d/d

dE/d

dE/d

Total TOTEM/CMS acceptance (*=1540m)

RPs

=172m=172m(prelim.)(prelim.)

K.Eggert/CERN

CMS/TOTEM PhysicsCMS/TOTEM Physics

CMS / TOTEM detector ideal for study of diffractive and forward physicsCMS / TOTEM detector ideal for study of diffractive and forward physics

Soft and hard diffraction in Single and Double Pomeron Exchangeproduction of jets, W, J/, heavy flavours, hard photons

Excellent proton measurement: gap survival

Double Pomeron exchange as a gluon factory

Production of low mass systems (SUSY, ,D-Y,jet-jet, …)

Glue balls, …

Higgs production ???

Structure functions (parton saturation) with and without detected protons

Forward physics: DCC, particle and energy flow

physics

K.Eggert/CERN

TOTEM+CMS Physics: Diffractive EventsTOTEM+CMS Physics: Diffractive Events

X

XDoublePomeronExchange

-Triggered by leading proton and seen in CMS-Central production of states X: X = c, b, Higgs, dijets, SUSY particles, ...

Measure > 90% of leading protons with RPs and diffractive system ‘X’ with T1, T2 and CMS.

K.Eggert/CERN

Running ScenariosRunning Scenarios

ScenarioScenarioPhysics:Physics:

11low |t| elastic,low |t| elastic,

tot tot ,,

min. bias, min. bias, soft diffractionsoft diffraction

22large |t| large |t| elasticelastic

33diffractiondiffraction

44hard hard

diffractiondiffraction

(under study)(under study)

** [m] [m] 15401540 1818 15401540 170170

N of bunchesN of bunches 4343 28082808 156156 28082808

N of part. per bunchN of part. per bunch 0.3 x 100.3 x 101111 1.15 x 101.15 x 101111 (0.6 - 1.15) x (0.6 - 1.15) x 10101111

1.15 x 101.15 x 101111

Half crossing angleHalf crossing angle

[[rad]rad]

00 160160 00 150150

Transv. norm. emitt. Transv. norm. emitt. [[m rad]m rad]

11 3.753.75 1 - 3.751 - 3.75 3.753.75

RMS beam size at RMS beam size at IP [IP [m]m]

454454 9595 454 - 880454 - 880 270270

RMS beam diverg. RMS beam diverg.

[[rad]rad]

0.290.29 5.285.28 0.29 - 0.570.29 - 0.57 1.71.7

Peak luminosityPeak luminosity

[cm[cm-2-2 s s-1-1]]

1.6 x 101.6 x 102828 3.6 x 103.6 x 103232 2.4 x 102.4 x 102929 ~ 0.5 10~ 0.5 103232

K.Eggert/CERN

TOTEM

log()

log(-t)

Diffractive protons are observed in a large -t range> 90% are detected

-t > 2.5 10 -3 GeV2

10-8 < < 0.1

resolution ~ few ‰

Diffractive protons at *=1540 m

K.Eggert/CERN

Diffractive proton detection at 0.5 m> 2.5 %

mm

log

log -t

420

(mm)

(mm)(mm)

(mm)

log -t

log

K.Eggert/CERN

New optics m

• Ly large (~270 m)

tmin =2 x 10-2 GeV2

• Lx ~ 0 independent

• Vertex measured by CMS

determination with a precision of few 10 -4

To optimize diffractive proton detection at L=1032 in the “warm” region at 220m

Lyy Lxx+vxx+D

=0-2

10m (CMS)

30mm

~ 65% of all diffractive protons are seen

10 beam

K.Eggert/CERN

Diffractive protons at =172 m

Log() vs Log(-t)

TOTEM

Pre

limin

ary

Log() vs Log(-t)

TOTEM

Prelim

inar

y

420

K.Eggert/CERN

Conclusion on new optics (*=172 m) - preliminary

• Luminosity of 0.5 x 1032 cm-2 s-1

• About 65% of diffractive protons are seen in the RP at 220 m

• resolution of 4 10 -4

• resolution of few rad

Future: • more detailed studies on resolution

• further optimization towards higher luminosities

K.Eggert/CERN

Example ProcessesExample Processes

2

22 '

p

pp

P

p1

p2p2’

X d/dproton:p2’

diffractive system Xrapidity gap =–ln

min 0ln(2pL/pT)max

Measure leading proton ( and rapidity gap ( test gap survival).

Single Diffraction:

2=– ln 1=– ln

p1

p2 p2’

p1’

PMX

2 = s

P

X

diffractive system Xproton:p2’

proton:p1’

rapidity gaprapidity gap

min max

Double Pomeron Exchange:

Measure leading protons ( 1, 2) and compare with MX, 1, 2

MX2 = s

K.Eggert/CERN

Exclusive Central DiffractionThe Pomeron has the internal quantum numbers of vacuum.

PP: C = +, I=0,...

P: JP = 0+, 2+, 4+,...

PP: JPC = 0++

Gap GapJet+Jet

p1

p2p2’

p1’

P

P

diffractive systemproton:p2’proton:p1’

rapidity gaprapidity gap

min max

min max

Signature:2 Leading Protons &2 Rapidity Gaps

Exclusive physics Gluon factory Threshold scan for New Physics

Large mass objects O(1TeV)

c: 10 6-7 events before decay

b: 10 3-4 events before decay

- a precursor to DPE Higgs, SUSY

K.Eggert/CERN

Exclusive Production by DPE: ExamplesExclusive Production by DPE: Examples

Advantage: Selection rules: JP = 0+, 2+, 4+; C = +1 reduced background, determination of quantum numbers.Good resolution in TOTEM: determine parity: P = (-1)J+1 d/d~ 1 +– cos 2

ParticleParticle exclexcl Decay channelDecay channel BRBRRate at Rate at

22xx10102929 cm cm-2-2 s s-1-1

Rate at Rate at

10103131 cm cm-2-2 s s-1-1

(no acceptance / analysis cuts)(no acceptance / analysis cuts)

c0c0

(3.4 GeV)(3.4 GeV)3 3 b b [KMRS][KMRS]

J/J/ ++––

+ + – – KK+ + KK––

6 x 106 x 10-4-4

0.0180.018

1.5 / h1.5 / h

46 / h46 / h

62 / h62 / h

1900 / h1900 / h

b0b0

(9.9 GeV)(9.9 GeV)4 nb 4 nb [KMRS][KMRS] ++–– < 10< 10-3-3 0.07 / d0.07 / d 3 / d3 / d

HH

(120 GeV)(120 GeV)

0.1 0.1 100 fb 100 fb

assume 3 fbassume 3 fbbbbb 0.680.68 0.02 / y0.02 / y 1 / y1 / y

Higgs needs L ~ 1033 cm-2 s-1, i.e. a running scenario for = 0.5 m:• try to modify optics locally,• try to move detectors closer to the beam,• install additional Roman Pots in cold LHC region at a later stage.

K.Eggert/CERN

y = – ln

ymax = 6.5

Trigger via Roman Pots > 2.5 x 10-2

Trigger via rapidity gap < 2.5 x 10-2

* = 1540 m: ~ 0.5% L 2.4 x 1029 cm-2 s-1

* = 172 m: ~ 0.2 - 0.4 L ~ 0.5 1032 cm-2 s-1

* = 0.5 m: ~ 0.2-0.6 ‰ L ~ 1033 cm-2 s-1

Detection Prospects for Double Pomeron EventsDetection Prospects for Double Pomeron Events

dN/dy

– ln – ln

y

pp

CMS

CMS + TOTEM

p1

p2 p2’

p1’

PM2 = s

P

* = 0.5 m

K.Eggert/CERN

ExHume

Phojet

log -t

log -t

log

log

input

and t distributions for 120 GeV Higgs

Proton acceptance 68%

Proton acceptance 63%

Detected protons at 220 m

K.Eggert/CERN

ExHume

Phojet

Mass Acceptance in DPE (preliminary)

=172 m

=0.5 m

220 m

420 m

420 + 220 m

ExHume

Phojet

Totem

Prelim

inar

y

K.Eggert/CERN

420m PHOJET

Asym. 420+215 m

420m EXHUME

Mass resolution at 420 m and 420+220m

Note:beam position accuracy 10 m

K.Eggert/CERN

p1

p2 p2’

p1’

PMX

2 = s

P

X

DPE cross-sections

=1540 m ∫L dt = 40 nb-1

3days

=172 m ∫L dt = 10 pb-1

3days

c0 3b x BR(10-3) ~ 3 nbb0 4nb x BR(10-3) ~ 4 pb

• pp pXp ~ 0.1 - 1 mb• pp p j1 j2 p ptjet >10 GeV inclusive ~ 1 b exclusive ~ 7 nb

jet-jet background to the Higgs:• pp p j1 j2 p

M(j1 j2) = 120 GeV exclusive ~ 18 pb / M= 10 GeV (Eur. Phys. J.C25,391)

K.Eggert/CERN

K.Eggert/CERN

ConclusionsConclusions

Measure Measure total cross-section total cross-section tot tot with a precision of with a precision of 1 % 1 % LL = ~10 = ~1028 28 cmcm-2-2 s s-1-1 with with * * = 1540 m= 1540 m

Measure Measure elastic scatteringelastic scattering in the range in the range 10 10 -3-3 < t < 8 GeV < t < 8 GeV 22

With the same dataWith the same data study of study of soft diffraction and forward physicssoft diffraction and forward physics::~ 10~ 1077 single diffractivesingle diffractive events events~ 10~ 1066 double Pomerondouble Pomeron events events

With With * * = 1540 m optics at = 1540 m optics at LL = 2 = 2 10 1029 29 cmcm-2-2 s s-1-1 : :semi-hard diffraction (psemi-hard diffraction (pTT > 10 GeV) > 10 GeV)

With With * * = 170 m optics (under study) at = 170 m optics (under study) at LL ~ 0.5 10 ~ 0.5 1032 32 cmcm-2-2 s s-1-1::hard diffraction and DPEhard diffraction and DPE

Study of rare events (Higgs, Supersymmetry,…) with Study of rare events (Higgs, Supersymmetry,…) with * = 0.5 m* = 0.5 musing eventually detectors in the cold region (420m)using eventually detectors in the cold region (420m)

TOTEM and CMS will write a common physics LOI in 2005

K.Eggert/CERN

K.Eggert/CERN

DiffractionDiffraction

Exchange of colour singlets (“Pomerons”) rapidity gaps Most cases: leading proton(s) with momentum loss p / p

P() = e-, = dn/d

p

p

g, qg, q

Exchange of colour triplets or octets:Gaps filled by colour exchange in hadronisation

Exponential suppression of rapidity gaps:

p

p

p

p

P

P

Unlike minimum bias events:

Example:

K.Eggert/CERN

02

2

1

16L

t

tot dt

dN

inelasticelastictot NN L inelel

ttot NN

dtdN

0

2

)/(

1

16

Optical Theorem

T1:3.1 << 4.7

T2: 5.3 < < 6.5

K.Eggert/CERN

Determination of the emission angle via the measurement at RP-147 m

x (147 m)

precision ~ few rad

K.Eggert/CERN

Measurement of Measurement of tottot

Measurement of the total cross section with the luminosity Measurement of the total cross section with the luminosity independent method using theindependent method using the Optical TheoremOptical Theorem..

02

2

1

16L

t

tot dt

dN

inelasticelastictot NN L inelel

ttot NN

dtdN

0

2

)/(

1

16

Measurement of the elastic and inelastic rate with a precision better than 1%.

K.Eggert/CERN

Particle elongation (x) for Lx=0 and different -values

Lx = 0

x(m)x(m)

s(m) s(m)

Example at =0.007 and different emission angles

Lx=0

Lx

K.Eggert/CERN

X22

0-x

216 (m

)

(x220+x216)/2 (mm)

2

2

=172 m: resolution ~ 4 10-4 (preliminary)

TOTEM

Prelim

inar

y

= 10-3 2 10-3

K.Eggert/CERN

Detector Layout y(m

m)

y(m

m)

y(m

m)

x(mm) x(mm) x(mm)

Leading diffractive protons seen at different detector locations (* = 0.5m)

215m 300m 420m

Dispersion D = 0.08 m D=0.7m D=1.5m