SIGNAL ANDSIGNAL AND BACKGROUNDBACKGROUND

SIMULATION AT THE SIMULATION AT THE RECOMBINATION RECOMBINATION

CHAMBERCHAMBER

Vadim TALANOVVadim TALANOV

CERN and IHEP, ProtvinoCERN and IHEP, Protvino

Joint LHC Machine-Experiments WorkshopJoint LHC Machine-Experiments Workshopon Very Forward Detectorson Very Forward Detectors

CERN January 25 2007CERN January 25 2007

A BIT OF HISTORY…A BIT OF HISTORY…

The start of the studies: need to estimate the The start of the studies: need to estimate the background from the p-p collisions at the IP in the background from the p-p collisions at the IP in the BLMs associated with the RPs in IR1/5BLMs associated with the RPs in IR1/5 For the TOTEM Roman Pots located between TAN and D2For the TOTEM Roman Pots located between TAN and D2

The intermediate sources of the signal and The intermediate sources of the signal and background were found of interest for other background were found of interest for other groupsgroups Primaries from the IP – for the flux of the neutral particlesPrimaries from the IP – for the flux of the neutral particles Cascade simulation results at the TAN – for the background analysis in Cascade simulation results at the TAN – for the background analysis in

the forward detectorsthe forward detectors

STAGES OF CALCULATIONSTAGES OF CALCULATION

Multi-staged scheme of the cascade simulationsMulti-staged scheme of the cascade simulations

DPMJET to get the primaries from the p-p DPMJET to get the primaries from the p-p interactions and to analyze the source terminteractions and to analyze the source term

FLUKA to take the generated sources and FLUKA to take the generated sources and transport the secondary cascades in the layout of transport the secondary cascades in the layout of the LSS down to the TANthe LSS down to the TAN

SOURCE SCORING ZONESSOURCE SCORING ZONES

at TASat TAN

19.05m from IP5

139.8m from IP5

DPMJET SOURCE AT THE IPDPMJET SOURCE AT THE IP

DPMJET version 3.0-4 usedDPMJET version 3.0-4 used

Two sets of sources generatedTwo sets of sources generated 7x7 TeV, horizontal crossing with 285 7x7 TeV, horizontal crossing with 285 µµradrad 450x450 GeV and no crossing450x450 GeV and no crossing

Analyzed with/without cut on |Analyzed with/without cut on |ηη|>7.8|>7.8 0.8924 mrad = 17 mm 0.8924 mrad = 17 mm (TAS half aperture) (TAS half aperture) / 19.05 m/ 19.05 m

PARTICLE FLUX AT THE TASPARTICLE FLUX AT THE TAS

RED: number of particles per 1 p-p event from the IPRED: number of particles per 1 p-p event from the IP BLUE: inside TAS aperture at BLUE: inside TAS aperture at ||ηη|>7.8|>7.8 only only

7 TeV 450 GeV

ENERGY FLUX AT THE TASENERGY FLUX AT THE TAS

RED: energy [GeV] per 1 p-p event from the IPRED: energy [GeV] per 1 p-p event from the IP BLUE: inside TAS aperture at BLUE: inside TAS aperture at ||ηη|>7.8|>7.8 only only

7 TeV 450 GeV

A COMMENT ON DPMJETA COMMENT ON DPMJET

Energy flux with DPMJET3 in the region of |Energy flux with DPMJET3 in the region of |ηη|>7.8 |>7.8 —— ~10.3 TeV/event ~10.3 TeV/event

This value can be directly compared with the one This value can be directly compared with the one from the previous DPMJET versionsfrom the previous DPMJET versions CMS Muon TDR p.398 CMS Muon TDR p.398 —— ~8.9 TeV/event ~8.9 TeV/event CMS Note 2000-051 p.1 CMS Note 2000-051 p.1 —— ~8.5 TeV/event ~8.5 TeV/event

A result of the change in the DPMJET forward A result of the change in the DPMJET forward physics models (?)…physics models (?)…

PARTICLE FLUX AT THE IPPARTICLE FLUX AT THE IP

7 TeV

450 GeV

All particles

γ+π0 n7 TeV 7 TeV

All particlesγ+π0 n

450 GeV 450 GeV

PARTICLE FLUX AT |PARTICLE FLUX AT |ηη|>7.8|>7.8

7 TeV

All particles

γ+π0 n7 TeV 7 TeV

450 GeV

All particles

γ+π0 n450 GeV 450 GeV

5.5 cmat TAN

5.5 cmat TAN

CASCADE SIMULATIONS IN IR5CASCADE SIMULATIONS IN IR5

DPMJET generated events with the cut at DPMJET generated events with the cut at ||ηη|>7.8 |>7.8 used as a primary sourceused as a primary source

FLUKA 2006.3 used for the cascade simulationsFLUKA 2006.3 used for the cascade simulations

Collision optics 6.5 at 7 TeV and 450 GeVCollision optics 6.5 at 7 TeV and 450 GeV

Particle distributions recorded and analyzed at Particle distributions recorded and analyzed at the TAN central area (the TAN central area (±±5.5cm in X,Y)5.5cm in X,Y)

PARTICLE FLUX AT THE TANPARTICLE FLUX AT THE TAN

RED: number of primary (from the IP) particles at the TANRED: number of primary (from the IP) particles at the TAN BLUE: total number of particles per 1 p-p eventBLUE: total number of particles per 1 p-p event

7 TeV 450 GeV

ENERGY FLUX AT THE TANENERGY FLUX AT THE TAN

RED: energy [GeV] of primary (from the IP) particles at the TANRED: energy [GeV] of primary (from the IP) particles at the TAN BLUE: total energy of particles per 1 p-p eventBLUE: total energy of particles per 1 p-p event

7 TeV 450 GeV

AVERAGE ENERGY AT THE TANAVERAGE ENERGY AT THE TAN

RED: average energy [GeV] of primary particles at the TANRED: average energy [GeV] of primary particles at the TAN BLUE: energy of all particles per 1 p-p eventBLUE: energy of all particles per 1 p-p event

7 TeV 450 GeV

COMPARISON OF THE COMPARISON OF THE ESTIMATESESTIMATES

Flux and spectra estimates are cross-checked Flux and spectra estimates are cross-checked with the existing datawith the existing data N.Mokhov (Fermilab, MARS) and H.Menjo (Nagoya University, EPICS)N.Mokhov (Fermilab, MARS) and H.Menjo (Nagoya University, EPICS)

EPICS: nice agreement at 7 TeV (450 GeV in EPICS: nice agreement at 7 TeV (450 GeV in progress)progress) Particle spectra and average energy comparedParticle spectra and average energy compared

MARS: Good agreement on average quantitiesMARS: Good agreement on average quantities Total P[W@10Total P[W@103434(8x10(8x1088 p-p inelastic interaction/s)] = 168 vs. 164 (NM) p-p inelastic interaction/s)] = 168 vs. 164 (NM) Factor ~2 difference in total multiplicity and average energyFactor ~2 difference in total multiplicity and average energy

HADRON FLUX AT THE TANHADRON FLUX AT THE TAN

LEFT: DPMJET-FLUKA, RIGHT: LHC Report 633 hadron (with E>20 MeV) LEFT: DPMJET-FLUKA, RIGHT: LHC Report 633 hadron (with E>20 MeV) flux density at the TANflux density at the TAN

For the rate of 8For the rate of 8101088 p-p inelastic interactions/s in IP5 p-p inelastic interactions/s in IP5

DPMJET+FLUKA2006.3

PARTICLE SPECTRA AT THE PARTICLE SPECTRA AT THE TANTAN

LEFT: DPMJET-FLUKA, RIGHT: LHCf data by H.MenjoLEFT: DPMJET-FLUKA, RIGHT: LHCf data by H.Menjo For the rate of 8For the rate of 8108 p-p inelastic interactions/s in IP5108 p-p inelastic interactions/s in IP5

DPMJET+FLUKA

LHCfdata2x10

3

5x104

50 GeV

106

CONCLUSIONCONCLUSION

DPMJET-FLUKA cascade simulation scheme DPMJET-FLUKA cascade simulation scheme established for the LSSsestablished for the LSSs

Calculations for the particle flux and energy Calculations for the particle flux and energy distribution for the forward detectors in the TAN distribution for the forward detectors in the TAN performed for 7 TeV and 450 GeV operationperformed for 7 TeV and 450 GeV operation

The results checked with the existing data and The results checked with the existing data and found coherentfound coherent

The source files will be available for the analysis The source files will be available for the analysis in the experimental groupsin the experimental groups

BACK-UP SLIDESBACK-UP SLIDES

PARTICLE FLUX AT 450 GEVPARTICLE FLUX AT 450 GEV

PARTICLE FLUX AT 7 TEVPARTICLE FLUX AT 7 TEV

PARTICLE SPECTRA AT THE PARTICLE SPECTRA AT THE TANTAN

7 TeV 450 GeV

COMPARISON WITH MARS (1)COMPARISON WITH MARS (1)

FROM IP <N> <E> (GeV) p 7.8106E-06 1.3928E+03 n 1.8278E-01 2.9556E+03 p+ 3.9053E-05 1.4448E+03 p- 1.2583E-03 2.5358E+03 K+ 3.9053E-05 1.5920E+03 K- 1.8779E-04 2.6675E+03 m+ 0.0000E+00 0.0000E+00 m- 0.0000E+00 0.0000E+00 g 6.4190E+00 7.9219E+01 e+ 2.3936E-01 3.3844E-01 e- 9.6830E-02 1.2591E+00 pbar 1.4059E-04 2.8715E+03 K0L 3.6506E-02 1.2308E+03 K0S 4.8158E-03 2.2434E+03 L 2.2313E-02 3.5788E+03 Lbar 6.3297E-04 1.8356E+03 S- 1.5640E-05 2.3074E+03 nbar 1.2447E-02 1.1503E+03

N.Mokhov TAN WS 10.03.06 p.7

COMPARISON WITH MARS (2)COMPARISON WITH MARS (2)

TOTAL <N> <E> (GeV) p 7.3862E-02 1.5663E+02 n 4.8929E-01 1.1694E+03 p+ 1.8048E-01 2.6559E+01 p- 2.0284E-01 4.9450E+01 K+ 1.3632E-02 2.3149E+01 K- 1.1683E-02 5.7245E+01 m+ 3.3441E-04 6.3382E+00 m- 7.6302E-04 9.9281E+00 g 9.5767E+01 5.4964E+00 e+ 6.1432E+00 1.5946E-01 e- 5.8856E+00 1.8103E-01 pbar 5.2652E-03 1.7274E+02 K0L 4.8855E-02 9.2650E+02 K0S 5.0332E-03 2.1485E+03 L 2.2313E-02 3.5788E+03 Lbar 6.3297E-04 1.8356E+03 S- 1.5640E-05 2.3074E+03 nbar 1.8694E-02 8.2330E+02

N.Mokhov TAN WS 10.03.06 p.7