# Presentation: 604636

##    TOTEM Physics Scenarios at the LHC;

-       Elastic Scattering, Total Cross section, Diffraction,
-       and beyond ...

-               Risto Orava
-  Helsinki Institute of Physics
-                     and
-        University of Helsinki

**               ****LOW X MEETING                                                      SINAIA, ROMANIA**
**                                                                                       ****June 29 - July 2 - 2005 **

## TOTEM Experiment

- CMS Experimental Area (IP5)

- Leading Protons measured at
- +147m & +220m from the CMS

- Leading Protons measured at
- -220m & -147m from the CMS

- (Also CMS is here...)

-  Leading protons are detected at 147m & 220m from the IP.
-  CMS coverage is extended by Totem T1 and T2 spectrometers.
-  Additional forward calorimetry & veto counters are under planning.

-             CMS  is  TOTEMized...

## LHC TOTEMized

**0**

**-12**

**-10**

**-8**

**-6**

**-4**

**-2**

**+2**

**+4**

**+6**

**+8**

**+10**

**+12**

- 

- pT (GeV)

- 0.1

- 1

- 10

- 100

- 1000

**CMS**

**ATLAS**

**ALICE**

**LHCb**

-     Base Line LHC Experiments: pT- coverage

| Exp |      B 
   (T) |    pT
(GeV) |
| --- | --- | --- |
| ALICE | 0.2-0.5 | 0.1-0.25 |
| ATLAS |   2.0 |    0.5 |
| CMS |   4.0 |    0.75 |
| LHCb |  4Tm |    0.1 |

- The base line LHC experiments will cover the _central _rapidity region
- - TOTEMCMS will complement the coverage in the _forward_ region.

**T1**

**T1**

**T2**

**T2**

**RP**

**RP**

**microstation**

**microstation**

**veto**

**veto**

- pTmax ~ s exp(-)

##             Base Line LHC Experiments

-  Energy flow in || 5
-  Minimum bias event structure
-  need to sort out the pile-up events at L › 1033
-  present MC models differ by large factors
- ALICE:
-  Charged multiplicities in -5    3
-  Zero Degree Calorimetry (neutral & charged)
**TOTEM:**
-  Charged multiplicities: 3    7
-  Leading particle measurement:
-  Totem sees ~ all diffractively scattered protons
-  TOTEM/CMS inelastic coverage is unique:
-   Holes only at  ~ 5 & 7-9 (could be covered with s & veto counters)

-             Base Line LHC Experiments

## +

-     A hard scale + hadrons which remain intact in the scattering process.

- Soft diffractive scattering:
- large b

- Hard diffractive scattering
- - small b

- Valence quarks in a bag with
- r  0.1fm

- Baryonic charge distribution-r  0.5fm

- Rapidity gap
- survival & ”underlying”
- event structures are
- intimately connected
- with a geometrical
- view of the scattering
- - eikonal approach!

- Longitudinal view
- - Lorentz contracted – not to scale!

- 

- p

- p

- lnMX2

- jet

- jet

- Elastic

- soft
- SDE

- hard
- SDE

- hard
- CD

- Totem sees SDE MX  20 GeV

- lns

- rapidity

- Cross sections are _large_.

- 10mb?

- 25mb?

- 1mb?

- Hard processes:
- Jet momenta
- correlated
- with the initial
- parton momenta.

- Soft processes:
- Coherent
- interactions
- impact parameter
- picture.

- Transversal view

- ‘wee’ parton cloud - grows logarithmically

**b**

**b**

- soft
- CD

##          A Light Higgs Boson as a Benchmark: Recent Tevatron Top-mass 

- The new result (using 173.5  4.1 GeV/CDF): Central preferred value of the Standard Model Higgs boson mass is: 	**94 GeV, with 68% uncertainties of +54 and -35 GeV****. **
**	****	****95% C.L is < 208 GeV**** **
- Thanks to Martin Grunewald

-          A Light Higgs Boson as a Benchmark: Recent Tevatron Top-mass
-          measurement reinforces the motivation.

##     Central Diffraction produces two leading protons,  

-     Central Diffraction produces two leading protons,
-     two rapidity gaps and a central hadronic system. In the
-     exclusive process, the background is suppressed and the
-     central system has selected quantum numbers.

- JPC = 0++ (2++, 4++,...)

- Gap

- Gap

- Jet+Jet

- 

- 

- 

- 

- min

- max

- Survival of the rapidity gaps?1

- see: DKMOR EPJC25(2002)391

- Measure the parity P = (-1)J:
- d/d  1 + cos2

- Mass resolution  S/B-ratio

- MX212s

## With the leading protons and additional forward      coverage a new physics realm opens up at the LHC:

_**Hard diffraction**_** with multi- rapidity gap events (see: Hera, Tevatron, RHIC...)**
-       ****** ****Problems intimately related to **_**confinement**_**.**
- Gluon density at small xBj (10-6 – 10-7) – “hot spots” of glue in vacuum?
- Gap survival dynamics, proton parton configurations (pp3jets+p) – underlying event structures
- Diffractive structure: Production of jets, W, J/******, **b, t, hard photons,
- Parton saturation, BFKL dynamics, proton structure, multi-parton scattering
- Studies with _pure gluon jets_: gg/qq...  **LHC as a **_**gluon factory**_**! ****(see: KMR EPJC19(2001)477)**
_**Signals of new physics**_** based on forward protons**** + rapidity gaps**
-        _**Threshold scan**_ for JPC = 0++ states in: pp  p+X+p
- 	    – Spin-parity of X ! (LHC as the pre -e+e- linear collider in the -mode.)
_**Extend  ‘standard’ physics reach**_** of the CMS experiment into the forward region:**
-        ****** ****Full Monty!**
_**Measure the Luminosity**_**  with the precision of ********L/L******** 5 % ****(KMRO EPJC19(2001)313)**** **

- Elastic scattering, tot and soft diffraction – surely...
**But **_**also**_**:**

## As a Gluon Factory LHC could deliver...

**As a Gluon Factory LHC could deliver...**

-  _High purity_ (q/g ~ 1/3000) gluon jets with ET > 50 GeV;
-  gg-events as “Pomeron-Pomeron” luminosity monitor
-  Possible _new resonant states _in a _background free_ environment (bb, W+W- &
- +- decays); (see: KMR EPJC23(2002)311)
* **Higgs*
* **glueballs*
* **quarkonia 0**++ **(****b** )*
* **gluinoballs*
-  invisible decay modes of Higgs (and SUSY)!?
-  CP-odd Higgs
-  *Squark & gluino* _thresholds are well separated_
-  practically background free signature: multi-jets &  ET
-  model independence (missing mass!) [expect O(10) events for gluino/squark masses of 250 GeV]
-  an interesting scenario: gluino as the LSP with mass window 25-35 GeV(S.Raby)
-  Events with isolated _high mass ___  pairs
* *Moreover: *Mini-Black Holes, Extra Dimensions –** *_*The Brane World !!!.*__.._
*                    **(see: Albrow and Rostovtsev)*

- -

## Low-x Physics at the LHCResolving Confinement of quarks & gluons?

- J. Stirling

- Low-x Physics at the LHCResolving Confinement of quarks & gluons?

- The forward detectors at the LHC will facilitate studies of collisions between
- transversally extended slices of QCD vacua – with quantum fluctuations?

##    Probing Very Small-x Gluons

- Instrument                   region with tracking,
- calorimetry (em+had), muons,
- jets, photons ...

- In SD: If a pair of high ET jets are produced, then:
- If the interacting partons have fractional momenta  of P, then =xBj/,
- then (if all hadrons i in the event are measured):

- Consider a high momentum proton:
- Measure gluon distribution G(x,Q2) at fixed Q2
- and small x with x››Q
-  probe gluons with the transverse size = |b|~1/Q and
-     longitudinal size = |z|~1/px.
-  gluon saturation, colour-glass condensates,
-     colour-dipoles,....

## Proton structure at low-x:

- Bjorken-x
- If rapidities above 5 and masses below 10 GeV can be
- covered
-  x down to 10**-6 **÷ 10**-7**
- Possible with T2 in TOTEM (calorimeter, tracker):
- 5 **< ******** < **6.7

- Parton saturation effects?

- Saturation or growing proton?

## Puzzles in High Energy Cosmic Rays

- Interpreting cosmic ray data depends on hadronic simulation programs.
- Forward region in poorly known.
- Models differ by factor 2 or more.
- Need forward particle/energy measurements
-   e.g.  dE/d...

- Cosmic ray
- showers:
- Dynamics of the
- high energy
- particle spectrum
- is crucial

- PYTHIA – PHOJET – ExHuME...??

## Chuck Dermer (BNL)

**Chuck Dermer (BNL)**

## The “Underlying Event” Problem inHard Scattering Processes

- Unavoidable background to be removed from the jets before comparing to NLO QCD predictions

- LHC:  most of collisions  are “soft’’,  outgoing particles roughly in the same direction as the initial protons.
- Occasional “hard’’ interaction results   in outgoing partons of large transverse momenta.
- The “Underlying Event’’ is everything but the two outgoing Jets, including :
-          initial/final gluon radiation
-          beam-beam remnants
-          secondary semi-hard interactions

***Min-Bias***

**Min-Bias**

- This is already of major importance at the Tevatron – how about the LHC??

## In addition: The signatures of New Physics have to be normalized  Measure the Luminosity

- Luminosity relates the number of events per second, dN/dt, and the cross section of process p, p, as:

- A process with well known, calculable and large p (monitoring!) with a well defined signature?   Need complementarity.**	**

- Measure simultaneously elastic (Nel) & inelastic rates (Ninel), extrapolate d/dt  0, assume -parameter to be known:

**       ****(1+********2****)         ****(N****el**** + N****inel****)****2**

**16********dN****el****/dt|****t=0**

**L =**

- Ninel = ?  	 	Need a hermetic detector.
- dNel/dtt=0 = ?   	Minimal extrapolation to t0: tmin  0.01

**see: KMOR EPJ C23(2002)**

##                Signatures

-  Proton (Roman Pots):
-  elastic proton (*=1540m: 5  10-4  -t  1 GeV2, *=18m: 310-1  -t   10 GeV2)
-  diffractive proton (*=1540m: 90% of _all_ diffractive protons:   10-2 & -t  10-3 GeV2)
-  hard diffractive proton (* = 0.5m: excellent coverage in -t space)
-  Rapidity Gap (T1 & T2, Castor & ZDC):
-  rapidity gaps (up to L~ 1033cm-2 s-1: 3  || 7, +veto counters?)
-  Very Fwd Objects (T1 & T2, Castor & ZDC):
-  Jets (up to L~ 1033cm-2 s-1: 3  || 7, +veto counters?)
-  , e, (fwd em calorimetry & muons: 3  || 7)
-  tracks (vx constraints & pattern recognition: 3  || 7)
-  particle ID?
-  Correlation with CMS Signatures (central jets, b-tags,...)

##   Correlation with the CMS Signatures

-  e, , , , and b-jets:
-  tracking: || < 2.5
-  calorimetry with fine granularity: || < 2.5
-  muon: || < 2.5
-  Jets, ETmiss
-  calorimetry extension: || < 5
-  High pT Objects
-  Higgs, SUSY,...
-  Precision physics (cross sections...)
-  energy scale: e &  0.1%, jets 1%
-  absolute luminosity vs. parton-parton luminosity via
- 	”well known” processes such as W/Z production?

##         Configuration of the Experiment

- b-jet

- b-jet

- CMS

-  Leading protons on both sides down to   1‰
- - Rapidity gaps on both sides – forward activity – for || > 5
-  Central activity in CMS

- -

- Aim at measuring the:

- Roman Pot
- Station at
- 147 / 220m

- Aim at detecting colour singlet exchange processes with the leading protons
- scattered at small angles with respect to the beam.

- Roman Pot
- Station at
- 147/220m

- CASTOR

- T1

- T1

- T2

- T2

- CASTOR

##     To Reach the Forward Physics Goals    

-  Extended Coverage of Inelastic Activity
-  CMS

-     To Reach the Forward Physics Goals
-     Need:

## Leading Protons – Transfer Functions

- To be detected, the leading protons have to deviate sufficiently from the nominal LHC beams    special LHC optics & detector locations for elastically scattered protons.

- - the _initial _transverse position and scattering angle at the IP

- the effective length, x,y(s) = value of the -function
-   along the beam line, * = x(s=0) = y(s=0) at the IP.

- - betatron phase advance

- - dispersion

- - magnification

- The proton trajectory, in the plane transverse with respect to the beam, at position s
- along the beam line, is given as:

## Leading Protons - Measurement

- RP1

- RP2

- RP3

- 220 m

- 180 m

- 147 m

**IP5****	****CMS Interaction Point**
**TAS ****	****Beam Absorber for secondaries between the IP and Q1**
- Qi    	Quadrupole Magnets
- TASA 	Beam Absorber for secondaries between Q1 and Q2
- TASB 	Beam Absorber for secondaries between Q2 and Q3
- DFBx	Cryogenic Electrical Feed-Boxfor Arc
- Di 	Dipole Magnet i
**TAN ****	****Beam Absorber for neutral secondaries before Q1-Q3**
- BSR	Synchrotron Radiation Observation System
**TCL ****	****Long Collimator for protecting Quadrupole Magnets**

- The small-angle protons are detected within the LHC beam pipe at large distances from the IP. To facilitate detection of elastically and diffractively scattered protons, special machine optics are needed  * = 1540m (-t down to  10-3 GeV2), 18m (-t up to 10 GeV2)
- For hard diffraction and low-x physics, nominal – high luminosity – conditions are required  * = 0.5m

- RPi: Special insertion devices needed
- for placing the proton detectors within
- the beam pipe
-  Roman Pots

- CMS

##     Leading Proton Detection-An Example 

- 147m

- 180m

**220m**

- 0m

- 308m

- 338m

**420 430m**

- 

- 

- 

- 

- 

- 

- 

- IP

- Q1-3

- D1

- D2

- Q4

- Q5

- Q6

- Q7

- B8

- Q8

- B9

- Q9

- B10

- B11

- Q10

- 

- 

- 

- 

- 

- 

- Helsinki group: Jerry Lamsa & RO

-  = 0.02

- Note the magnification x vs. z!

## Elastic Protons

** **Reduce number of bunches (43 and 156) to avoid parasitic interactions downstream.

**L****TOTEM**** **= 1.6 x 1028 cm-2 s-1  and  2.4 x 1029 cm-2 s-1

- For detecting the low –t elastic protons down to –t  10-3 GeV2 (scattering angles of a few mrad) need to maximise Lx(s=sRPi), Ly(s=sRPi)  at each RPi, and, simultaneously, to minimise vx(s=sRPi), vy(s=sRPi)    at each RPi.

-  low angular spread at IP:
-  large beam size at IP:

- (if N = 1 m rad)

****** ****High-********* optics: ********* = 1540 m**

***y********

- IP

*L**eff*

- Aim at *parallel-to-point focussing* condition: vx,y = 0 in both x- and y-directions at s=220m  independence of the initial transverse position of the IP.

## Elastic Scattering: d/dt

- Elastic Scattering: d/dt

- d/dt (mb/GeV2)

- -t (GeV2)

## Elastic Scattering: Acceptance in -t

- Interference,  meas.  510-4  510-3	[as above], standard * = 1540 m
- Pomeron exchange          510-3  0.1	* = 1540 m
- Diffractive structure	 0.1  1		* = 1540 m, 18 m
- Large |t| – perturb. QCD	  1  10		* = 18 m

- Region 			|t| [GeV]2		Running Scenario

## Elastic Scattering: Resolution

- t-resolution (2-arm measurement)

- -resolution (1-arm measurement)

- Test collinearity of particles in the 2 arms
-  Background reduction.

## Extrapolation of Elastic Cross-Section to t = 0

| Effect |  | Extrapolation uncertainty |
| --- | --- | --- |
| Statistics (10h @ 1028): | 107 events | 0.07 % |
| Uncertain functional form of d/dt |  | 0.5 % |
| Beam energy uncertainty | 0.05 % | 0.1 % |
| Beam / detector offset | 20 m | 0.08 % |
| Crossing angle | 0.2 rad | 0.1 % |
| Total |  | 0.53 % |

- Non-exponential d/dt fitted to
- Slope parameter
- according to BSW Model

**see: KMRO EPJ(2001)313**

## Soft Diffraction (high *): Acceptance

** ****-assuming                          **
****** ****= ********p/p can be measured with a resolution of ~ 5 x 10****-3**** .**

- Soft Diffraction (high** ***): Acceptance

- A < 5 %

- A > 95 %

- 85 - 95 %

******* = 1540 m**

## Hard Diffraction (high *): Acceptance

## Extension to Inelastic Coverage

- T1: 3.1 <****< 4.7
- T2: 5.3 <**  ****** < 6.5

- T1

- T2

- 10.5 m

- 10.5 m

- ~14 m

- CASTOR

- To measure the colour singlet exchange, need to extend central detector
- coverage in the forward direction:  > 5.

## Slide 32

## Total pp Cross-Section

- Aim of TOTEM: **~1%** accuracy

- LHC:

- TEVATRON

- ISR

- UA4

- UA5

- LHC

- Cosmic Rays

- COMPETE Collaboration fits:

- [PRL 89 201801 (2002)]

## Measurement of tot

- Luminosity-independent measurement of the total cross-section by using the Optical Theorem:

-  Measure the elastic and inelastic rate with a precision better than 1%.
-  Extrapolate the elastic cross-section to t = 0.
- Or conversely:
- Extract luminosity:

## Measurement of the Total Rate Nel + Ninel

|  |    [mb] | T1/T2        double arm trigger loss [mb] | T1/T2                  single arm          trigger loss [mb] | Uncertainty after extrapolation [mb] |
| --- | --- | --- | --- | --- |
| Minimum bias | 58 | 0.3 | 0.06 | 0.06 |
| Single diffractive | 14 | - | 2.5 | 0.6 |
| Double diffractive | 7 | 2.8 | 0.3 | 0.1 |
| Double Pomeron | 1 | ~ 0.2
(using leading p and CMS) |  | 0.02 |
| Elastic Scattering | 30 | - | - | 0.15 |

- Extrapolation of diffractive cross-section to large 1/M2 using d/dM2 ~ 1/M2 .

- Total: 0.8 %

## Accuracy of tot 

- Extrapolation to t = 0

- Total rate Nel + Ninel

****** ****= 0.12 ****± ****0.02**

##     Total Cross Section - TOTEM

-     Total Cross Section - TOTEM

- TOTEM

##       Elastic Scattering- TOTEM

-       Elastic Scattering- TOTEM

- TOTEM

## Running Scenarios

| Scenario
(goal) | 1
low |t| elastic,
tot , min. bias | 2
diffractive physics,
large pT phenomena |  | 3
intermediate |t|, 
hard diffraction | 4
large |t| elastic
 |
| --- | --- | --- | --- | --- | --- |
| * [m] | 1540 | 1540 |  | 200 - 400 | 18 |
| N of bunches | 43 | 156 |  | 936 | 2808 |
| Half crossing angle [rad] | 0 | 0 |  | 100 - 200 | 160 |
| Transv. norm. emitt. [m rad] | 1 | 1 | 3.75 | 3.75 | 3.75 |
| N of part. per bunch | 0.3 x 1011 | 0.6 x 1011 | 1.15 x 1011 | 1.15 x 1011 | 1.15 x 1011 |
| RMS beam size at IP [m] | 454 | 454 | 880 | 317 - 448 | 95 |
| RMS beam diverg. [rad] | 0.29 | 0.29 | 0.57 | 1.6 - 1.1 | 5.28 |
| Peak luminosity
[cm-2 s-1] | 1.6 x 1028 | 2.4 x 1029 |  | (1 - 0.5) x 1031 | 3.6 x 1032 |

- + Runs at ******* = **0.5 m, L = (1033   1034) cm-2 s-1 foreseen as an extension to the TOTEM program.

## Exclusive 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

| Particle | excl | Decay channel | BR | Rate at 
2x1029 cm-2 s-1 | Rate at 
1031 cm-2 s-1 |
| --- | --- | --- | --- | --- | --- |
|  |  |  |  | (no acceptance / analysis cuts) |  |
| c0
(3.4 GeV) | 3 b  [KMRS] |  J/   +–
+ – K+ K– | 6 x 10-4
0.018 | 1.5 / h
46 / h | 62 / h
1900 / h |
| b0
(9.9 GeV) | 4 nb  [KMRS] |   +– | 10-3 | 0.07 / d | 3 / d |
| H
(120 GeV) |  3 fb (2.5fb) | bb | 0.68 | 0.02 / y | 1 / y |

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

## Hard Diffraction: Leading Protons at Low *

- Hard Diffraction: Leading Protons at Low *

- CMS

- Dispersion in horizontal plane (m)

- x

- Optical function  in x and y (m)

- For a 2.5 mm offset of a   0.5 %  proton, need dispersion  0.5 m.
-  Proton taggers to be located at > 250 m from the IP (i.e. in a ”cryogenic section” of the LHC).

- y

- Dx

- horizontal offset  = Dx ( = momentum loss)

##    Potential locations for measuring the leading protons 

- Dispersion suppressor

- Matching section

- Separation dipoles

- Final focus

-    Potential locations for measuring the leading protons
-    in pp  p  X  p with MX ~ O(100 GeV).

- 420 m

- 220 m

- CMS

- (308/338m)

- Cryogenic (”cold”) region (with main dipole magnets)

- locations of currently planned TOTEM pots!!

##           The TOTEM Detector Layout 

- y(mm)

- y(mm)

- y(mm)

- x(mm)

- x(mm)

- x(mm)

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

- 220m

- ~300m

- 420m

- ~2-12mm

- ~1,5-20mm

- ~3,5-17mm

##    Exciting new physics potential in the 

-    process: pp  p  (JPC=0++)  p

- p

- p

- b-jet

- b-jet

- 

- 

- 

- p

- p

- p

- p

- b

- b

- 0

- 5

- -5

- 10

- -10

- -

- -

- P

- P

- Colour singlet exchange process with exclusive priviledges
-   - JPC selection rule
-    e+e- ILC type threshold scan for new physics!

**see: KMR EPJ(2002)**

-  Need to solve the L1 trigger issue at high luminosity (pile-up)
-   conditions.

## CD ExHuME (MH = 120 GeV)

**CD ExHuME (M****H**** = 120 GeV)**

- Higgs

- dN/dHiggs

##      Event Characteristics: d/dt & min

- dN/dt

- N/dt

- dN/dmin

- N/dmin

- -t (GeV2)

- -t (GeV2)

- min

- min

**CD PHOJET (M****H**** = 120 GeV)**

**CD PHOJET (M****H**** = 120 GeV)**

-  dN/dt  exp(-10t)

-  should detect p’s down to   10-3

- -t < 1 GeV2

- acceptance?

## CD ExHuME (MH = 120 GeV)

******min**

**dN/d********min**

******dN/d********min**

******min**

**CD ExHuME (M****H**** = 120 GeV)**

**0.0    0.001   0.002    0.003   0.004    0.005   0.006    0.007   0.008   0.009  0.010 **

**0.0    0.001    0.002    0.003   0.004    0.005   0.006    0.007   0.008    0.009  0.010 **

##           Where do the b-jets go?

-           Where do the b-jets go?

- bmax

- bmax

- dN/dbmax

- pmin  0.002

-  The b-jets are confined within  4.
-  ExHuME generates more symmetric jet pairs.

- pmax  0.02

- PHOJET

- PHOJET

- ExHuME

- ExHuME

## Leading protons: Hard CentralDiffraction

- Uncertainties included in the study:
-  Initial conditions at the interaction point
-  Conditions at detector location

- Position resolution of detector (x,y = 10 m)
- Resolution of beam position determination (x,y = 5 m)
- Off-sets at detector locations

-  pp   p + X + p simulated using PHOJET1.12& ExHuME
-  Protons tracked through LHC6.2& 6.5 optics using MAD

- Transverse vertex position (x,y = 11 m)
- Beam energy spread (E = 10-4)
- Beam divergence ( = 30 rad)

- J.Lamsa, T. Maki, R.Orava, K.Osterberg...

## Acceptance: ExHuME vs. PHOJET

- "420+220" calculation:  either both protons are detected at 420m, or both protons are detected at 220m, or one proton is detected at 420 [220]m with the other one detected at 220 [420]m.

**ExHuME 420+220m**

**PHOJET 420+215m**

**ExHuME 420m**

**PHOJET 420m**

- 60%

- 22%

- 38%

- 12%

- 420m+220m ExHuME
- 420m	   ExHuME
- 420m+220m PHOJET
- 420m           PHOJET

- Helsinki group: Jerry Lamsa et. al.

##        Resolution: ExHuME vs. PHOJET

-        Resolution: ExHuME vs. PHOJET

**ExHuME 420+220m**

**ExHuME 420m**

**PHOJET 420m**

**PHOJET 420+220m**

**2.8%**

**0.9%**

**3.7%**

- Helsinki group: J.Lamsa (parametrisations of the MAD simulation results of T. Mäki by RO)

- 420m+220m ExHuME
- 420m	   ExHuME
- 420m+220m PHOJET
- 420m           PHOJET

- Helsinki group: Jerry Lamsa et. al.

##       Rapidity Gap Veto – Detector Lay-Out

- veto counters

-  60m

- ~ 140m

- Q1

- Q2

- Q3

- D1

- IP

-       Rapidity Gap Veto – Detector Lay-Out

- magnification x vs. y: 70

**80cm**

**80cm**

##     Rapidity Gap Veto – Acceptance Summary

**TOTEM – in combination with CMS – represents an experiment with a unique coverage **
**in rapidity ******** collisions of extended sheets of QCD vacuum – ****branes in collision??**

- Helsinki group: Jerry Lamsa & RO

- Veto Acceptances

****

- Acceptance

**microstations at 19m?**

**Veto**

**RP’s**

**T2**

**T1**

##        TOTEM Physics Scenarios

- Proton
-  * (m)

- rapidity
- gap
-   L(cm-2s-1)

- jet

- inelastic
- activity

- ,e,,
- , ++,...

- elastic scattering

- total cross section

- soft diffraction

- hard diffraction

- ’1540’
-    ’18’

- ’1540’

-    ’1540’
-     ’170’

-     ’170’
-     ’ 0.5’

- low-x physics

- exotics (DCC,...)

- DPE Higgs, SUSY,...

- central
-   pair

- central
-  & fwd

- inelastic
- acceptance

-      gap
-   survival

-      jet
- acceptance

-    di-jet
-    backgr

- b-tag, ,
- J/,...

-     1028 -1032

-     1029 -1031

-     1028 -1033

-     1031 -1033

-     1031 -1033

- TOTEM
- & CMS

- TOTEM
- & CMS

- TOTEM
- & CMS

-    central
- & fwd jets

- di-leptons
- jet-

- mini-jets
- resolved?

- ± vs. o
- multiplicity

- leptons
- ’s

-       jet
- anomalies?

- W, Z,
- J/,...

- , K±,
- ,...

-      ’0.5’

-     1031 -1033

-     1031 -1033

-     ’170’
-      ’0.5’

-     ’170’
-      ’0.5’

- mini-jets?

- beam halo?

- trigger