April 22, 2006 DIS2006 XIV International Workshop on Deep Inelastic Scattering Tsukuba, Japan, 20-24/April/2006 1 TOTEM: Early Diffractive Physics at the

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April 22, 2006 DIS2006

XIV International Workshop on Deep Inelastic ScatteringTsukuba, Japan, 20-24/April/2006

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TOTEM: Early Diffractive Physics at the LHC

Jim WhitmorePenn State University

INFN Sezione di Bari and Politecnico di Bari, Bari,

Italy Case Western Reserve University, Cleveland,

Ohio,USA

CERN, Geneva, Switzerland

Estonian Academy of Sciences, Tallinn, Estonia

Università di Genova and Sezione INFN, Genova, Italy

Università di Siena and Sezione INFN-Pisa, Italy University of Helsinki and HIP, Helsinki, FinlandAcademy of Sciences, Praha, Czech Republic;Warsaw University of Technology, Plock,Poland Penn State University, University Park, USABrunel University, Uxbridge, UK

on behalf of the

TOTEM Collaboration

http://totem.web.cern.ch/Totem/

April 22, 2006 DIS2006


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

TOTEM PhysicsTOTEM Physics•Total cross-section tot with a precision of 1%

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

•Forward Physics:•Diffractive phenomena (together with CMS) with high cross-sections

•Measurement of leading particles

•Particle and energy flow in the forward direction

•Different running scenarios * = 1540, 90, 18, 0.5 m

See my plenary talk

Concentrate on these

April 22, 2006 DIS2006


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+TOTEM

April 22, 2006 DIS2006


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TOTEM Experiment(symmetric about IP5)

T1 & T2

RP

RP

April 22, 2006 DIS2006


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T1:3.1 << 4.7

T2: 5.3 < < 6.5

T1 T2 CASTOR (CMS)

RP1 (147 m) RP2 (180 m)(later option)

RP3 (220 m)

Experimental Apparatus

Experimental Apparatus

10.5 m~14 m

TOTEM + CMSTOTEM + CMS

pairs 4m apart

April 22, 2006 DIS2006


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• 5 planes with measurement of three coordinates per plane.

• 3 degrees rotation and overlap between adjacent planes

• Primary vertex reconstruction

• Trigger with CSC wires

T1 TelescopeT1 Telescope3.1< || <4.7

~3 m1 arm

April 22, 2006 DIS2006


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5.3< ll < 6.5GEM (Gas Electron Multiplier) Telescope: 10 ½-planes 13.5 m

from IP

T2 TelescopeT2 Telescope

Digital r/o pads

Analog r/o circular strips

40 cm

April 22, 2006 DIS2006


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TOTEM ROMAN POT IN CERN SPS BEAM

April 22, 2006 DIS2006


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Roman Pot unit:- Measurement of very small p scattering angles (few rad)- Vertical and horizontal pots mounted as close as possible- BPM fixed to the structure gives precise position of the beam- TOTEM at the RP: beam ≈ 80 m- Leading proton detection at distances down to 10beam + d- Need “edgeless” detectors that are efficient up to the physical edge to minimize “d”

0

recon

st r

ucte

d t

r ack

Tracks

Roman Pots

Roman Pots

Test beam data:

RP in SPS beam and the detector is measuring the halo

u,vinfo

reconstructedtracks in y

BPMBPM

April 22, 2006 DIS2006


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Planar technology: Testbeam 40 m dead area

Detector 1Detector 1 Detector 2Detector 2

active edges(“planar/3D”)

planar technology CTS(Curr. Termin. Struct.)

50

m

dead

are

a1

0

m d

ead

are

a66 m pitch

Add here photo of RP

Active edges: X-ray measurement

m

Sig

nal

[a.

u.]

5m deadarea

Strip 1 Strip 2

Edgeless silicon detectors for the RP

Edgeless silicon detectors for the RP

10 planes/pot

April 22, 2006 DIS2006


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High- optics for precise meas.t 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 downstream

LTOTEM ~ 1028-29 cm-2 s –1

TOTEM needs special/independent short runs at high-*1540mand lowScattering angles of a few rad

TOTEM Optics conditionsTOTEM Optics conditions

To optimize diffractive proton detection at L=1030-31 in the “warm” region at 220m

|tmin| = 3 x 10-2 GeV2

~ 65% of all diffractive protons are seen determination with a precision of few 10-4

New optics *= 90 mNew optics *= 90 m

Status: • easier than higher * (which needs special injection)• can be obtained by un-squeezing from 18 m injection optics

• TOTEM needs to estimate their accuracy of tot (~5%??)

April 22, 2006 DIS2006


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ScenarioPhysics:

1low |t| elastic,tot ,

min. bias, soft

diffraction

2diffraction

3large |t| elastic

4hard

diffractionlarge |t| elastic(under study)

* [m] 1540 1540 18 90

N of bunches 43 156 2808 156

N of part. per bunch (x1011)

0.3 0.6 - 1.15 1.15 1.15

Half crossing angle [rad]

0 0 160 0

Transv. norm. emitt. [m rad]

1 1 - 3.75 3.75 3.75

RMS beam size at IP [m]

454 454 - 880 95 200

RMS beam diverg. [rad]

0.29 0.29 - 0.57 5.28 2.4

Peak luminosity [cm-2 s-1]

1.6 x 1028 2.4 x 1029 3.6 x 1032 2 x 1030

Running ScenariosRunning Scenarios

For * = 0.5 m,See M. Ruspa’s talk

April 22, 2006 DIS2006


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pp total Cross-Section


• Measure the total rate (Nel+Ninel) , diff ~ 18 mb and min. bias ~65 mb, with an expected precision of 0.8 % (running for 1 day at L = 1.6 x 1028cm-2s-1).

• Extrapolate the elastic cross-section to t = 0: systematics dominated: 0.5 %(statistical error after 1 day: 0.07 %)

• ρ =Re f(0)/Im f(0) unknown; using COMPETE pred.: 0.2 %

1 %

( = 0.1361±0.0015+0.0058-0.0025

)

pp total cross sectionpp total cross section

221

116

el el tot

t o t o

el ineltot

d dN

dt L dt

N N

L

Luminosity-independent measurement using the Optical Theorem:

02

22

0

/16

1

1

16 /

el ttot

el inel

el inel

el t

dN dt

N N

N NL

dN dt

April 22, 2006 DIS2006


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• Current models predictions: 90-130 mb

• Aim of TOTEM: ~1% accuracy (~1 mb)

mb 1.41.2

2.1 5.111 totLHC:

COMPETE Collaboration fits all available hadronic data and predicts:

[PRL 89 201801 (2002)]Cudell et al.



E811-CDFdisagreement≈ 2.6mb

April 22, 2006 DIS2006


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~1.5 GeV2

Elastic scattering – from ISR to Tevatron

Elastic scattering – from ISR to Tevatron

April 22, 2006 DIS2006


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* = 1540 m

L = 1.6 x 1028 cm-2 s-1

(1)

104 per bin

of 10-3 GeV2

diffractive structure

Photon - Pomeron interference

pQCD

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) (3)

wide range of predictions

pp elastic scattering cross-section

pp elastic scattering cross-section

*=18 m

L = 3.6 x 1032 cm-2 s-1

(3)

~ 1/|t|8

tmin from

1.3 mm = 10+0.5mmat 220m RP

BSW = Bourrely,Soffer and Wu

B(s) = B0 + 2P’ ln (s/s0) ~ 20 GeV-2 at LHC

April 22, 2006 DIS2006


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Observations:

• fwd diffraction cross section increases• • diffractive peak shrinks

• interference dip moves to smaller t

• at –t 1 GeV2:

• d/dt 1/t8 • (3-gluon exchange)• little s dependence

Elastic Scattering Models (eg. Islam et al)Elastic Scattering Models (eg. Islam et al)

1/t8

BSW

Desgrolardet al

Islam et al

April 22, 2006 DIS2006


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0.375

Rel = el(s)/tot(s) Rdiff=[el(s) +SD(s) + DD(s)]/tot(s)

0.30

el 30% of tot at the LHC ? SD + DD 10% of tot (= 100-150mb) at the LHC ?

0.2

0.4

0.3

0.2

0.3

0.1

Elastic Scattering- el/totElastic Scattering- el/tot

3 4 53 4 65 6log(s/s0)

April 22, 2006 DIS2006


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90% (65%) of all diffractive protons are detected for * = 1540 (90) m

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

dN

ch/d

dE/d

dE/d

Total TOTEM/CMS acceptance

CMS

central

T1

HCal

T2 CASTOR

=90m=90m

RPs

=1540m=1540m

ZDC

Pseudorapidity: = ln tg /2

Energy flux

Charged particles

CMS + TOTEM: AcceptanceCMS + TOTEM: Acceptance

107 min bias events, incl. all diffractive processes, in 1 day with * =1540 m

April 22, 2006 DIS2006


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Diffraction at * = 1540 m Acceptance

Diffraction at * = 1540 m Acceptance

Diffractive protons are observed in a large -t range: =p/p; t=-(p)2

90% are detected-t > 2.5x10-3 GeV2

10-8 < < 0.1 resolution ~5x10-3

kinematically

excluded

RP at 220 m

acc. < 10%

April 22, 2006 DIS2006


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Diffraction at * = 90 m AcceptanceDiffraction at * = 90 m Acceptance

Resolution in : = 4x10-4

(prel.)L<2x1030 cm-2s-

1

65% of all diffractive protons are detected

April 22, 2006 DIS2006


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TOTEM+CMS Physics: Soft Diffractive Event

rates

TOTEM+CMS Physics: Soft Diffractive Event

rates

(limited by DAQ to ~1 kHz)

Scenario: (1) (2)* = 1540 m

See next

April 22, 2006 DIS2006


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Hard Diffractive EventsHard Diffractive EventsDiffractive events with high pT particles produced

M

M

hard

hard

DoublePomeronExchange

hard

p

pjet 1 (pT 1)jet 2 (pT 2)jet 3 (pT 3)

pgg

u

du

Single diffraction: pp p + 3j

Double diffraction: pp p jj Xp= 1 bpT > 10 GeVAcc = 29.3%Excl: = 7 nbpp p jj p

DPE: pp pXp = 1 mbAcc = 27.8%

for *=90 m and preliminary

April 22, 2006 DIS2006


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Particle production in Double Pomeron Exchange

Particle production in Double Pomeron Exchange

Quantum numbers are defined for exclusive particle production

Gluonic states c , b , Higgs, supersymmetric Higgs,…..

Use the LHC as a clean gluon-gluon collider

Use the LHC as a clean gluon-gluon collider

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

(typically < 0.1)

diffractive system Xproton:p2’

proton:p1’

rapidity gaprapidity gap

min max

2= – ln 1= – ln MX

2 = s

See M. Ruspa/ B. Cox talks

April 22, 2006 DIS2006


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

TOTEM + CMSDiffractive Physics: DPE

TOTEM + CMSDiffractive Physics: DPE

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

p1

p2 p2’

p1’

PX

Scenario (2) (4)* (m) = 1540 90

10-1

10-2

10-4

10-5

10-6

2x106 107

2x105 106

2x104 105

2000 104

200 103

200

Events / GeV day

L = 2x1029, 1030 cm-2s-1

20 102

MX [GeV]

10-3

dD

PE

/ dM

X [

mb

/ GeV

]

[Pomeron trajectory (t) = 1 + + ’ t ]

April 22, 2006 DIS2006


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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

Higgs needs L ~ 1033 cm-2 s-1, i.e. a running scenario for = 0.5 m:• trigger problems in the presence of overlapping events• install additional Roman Pots in cold LHC region (420 m) at a later stage

Exclusive Production by DPE: examples

Exclusive Production by DPE: examples

LHC (CMS+TOTEM):

See B. Cox’s talk

April 22, 2006 DIS2006


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Measure total cross-section tot with a precision of 1% L = ~1028 cm-2 s-1 with * = 1540 m

Measure elastic scattering in the range 10-3 < |t| < 8 GeV2

L = ~1032 cm-2 s-1 with * = 18 m → high |t|L = ~1028 cm-2 s-1 with * = 1540 m → low |t|

A study of soft diffraction and forward physics:

With * = 1540 m optics at L = 21029 cm-2 s-1 :semi-hard diffraction (pT > 10 GeV) ~ 2x107 single and double diffractive events/day ~ 106 double Pomeron events/day

With * = 90 m optics (still under study) at L ~ 2x1030 cm-2 s-1:

hard diffraction and DPE ~ 107 double Pomeron events/day

Status:Test beam (“TOTEMino”) in Fall 2006 for RP, T1 and T2TOTEM and CMS are writing a TDR for common diffractive

physics

SummarySummary

April 22, 2006 DIS2006


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Extra slidesExtra slides

April 22, 2006 DIS2006


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T2 TelescopeT2 Telescope

Documents

April 22, 2006 DIS2006 XIV International Workshop on Deep Inelastic Scattering Tsukuba, Japan, 20-24/April/2006 1 TOTEM: Early Diffractive Physics at the