1. SIGNAL AND BACKGROUND SIMULATION AT THE RECOMBINATION CHAMBER Vadim TALANOV CERN and IHEP, Protvino Joint LHC Machine-Experiments Workshop on Very Forward Detectors CERN January 25 2007

2. A BIT OF HISTORY… The start of the studies: need to estimate the background from the p-p collisions at the IP in the BLMs associated with the RPs in IR1/5 The start of the studies: need to estimate the background from the p-p collisions at the IP in the BLMs associated with the RPs in IR1/5 For the TOTEM Roman Pots located between TAN and D2 For the TOTEM Roman Pots located between TAN and D2 The intermediate sources of the signal and background were found of interest for other groups The intermediate sources of the signal and background were found of interest for other groups Primaries from the IP – for the flux of the neutral particles Primaries from the IP – for the flux of the neutral particles Cascade simulation results at the TAN – for the background analysis in the forward detectors Cascade simulation results at the TAN – for the background analysis in the forward detectors

3. STAGES OF CALCULATION Multi-staged scheme of the cascade simulations Multi-staged scheme of the cascade simulations DPMJET to get the primaries from the p-p interactions and to analyze the source term DPMJET to get the primaries from the p-p interactions and to analyze the source term FLUKA to take the generated sources and transport the secondary cascades in the layout of the LSS down to the TAN FLUKA to take the generated sources and transport the secondary cascades in the layout of the LSS down to the TAN

4. SOURCE SCORING ZONES at TAS at TAN 19.05m from IP5 139.8m from IP5

5. DPMJET SOURCE AT THE IP DPMJET version 3.0-4 used DPMJET version 3.0-4 used Two sets of sources generated Two sets of sources generated 7x7 TeV, horizontal crossing with 285 µrad 7x7 TeV, horizontal crossing with 285 µrad 450x450 GeV and no crossing 450x450 GeV and no crossing Analyzed with/without cut on |η|>7.8 Analyzed with/without cut on |η|>7.8 0.8924 mrad = 17 mm (TAS half aperture) / 19.05 m 0.8924 mrad = 17 mm (TAS half aperture) / 19.05 m

6. PARTICLE FLUX AT THE TAS RED: number of particles per 1 p-p event from the IP RED: number of particles per 1 p-p event from the IP BLUE: inside TAS aperture at |η|>7.8 only BLUE: inside TAS aperture at |η|>7.8 only 7 TeV450 GeV

7. ENERGY FLUX AT THE TAS RED: energy [GeV] per 1 p-p event from the IP RED: energy [GeV] per 1 p-p event from the IP BLUE: inside TAS aperture at | η |>7.8 only BLUE: inside TAS aperture at | η |>7.8 only 7 TeV450 GeV

8. A COMMENT ON DPMJET Energy flux with DPMJET3 in the region of | η |>7.8 — ~10.3 TeV/event Energy flux with DPMJET3 in the region of | η |>7.8 — ~10.3 TeV/event This value can be directly compared with the one from the previous DPMJET versions This value can be directly compared with the one from the previous DPMJET versions CMS Muon TDR p.398 — ~8.9 TeV/event CMS Muon TDR p.398 — ~8.9 TeV/event CMS Note 2000-051 p.1 — ~8.5 TeV/event CMS Note 2000-051 p.1 — ~8.5 TeV/event A result of the change in the DPMJET forward physics models (?)… A result of the change in the DPMJET forward physics models (?)…

9. PARTICLE FLUX AT THE IP 7 TeV 450 GeV All particles γ+π0γ+π0 n 7 TeV All particles γ+π0γ+π0 n 450 GeV

10. PARTICLE FLUX AT | η |>7.8 7 TeV All particles γ+π0γ+π0 n 7 TeV 450 GeV All particles γ+π0γ+π0 n 450 GeV 5.5 cm at TAN 5.5 cm at TAN

11. CASCADE SIMULATIONS IN IR5 DPMJET generated events with the cut at | η |>7.8 used as a primary source DPMJET generated events with the cut at | η |>7.8 used as a primary source FLUKA 2006.3 used for the cascade simulations FLUKA 2006.3 used for the cascade simulations Collision optics 6.5 at 7 TeV and 450 GeV Collision optics 6.5 at 7 TeV and 450 GeV Particle distributions recorded and analyzed at the TAN central area (±5.5cm in X,Y) Particle distributions recorded and analyzed at the TAN central area (±5.5cm in X,Y)

12. PARTICLE FLUX AT THE TAN RED: number of primary (from the IP) particles at the TAN RED: number of primary (from the IP) particles at the TAN BLUE: total number of particles per 1 p-p event BLUE: total number of particles per 1 p-p event 7 TeV450 GeV

13. ENERGY FLUX AT THE TAN RED: energy [GeV] of primary (from the IP) particles at the TAN RED: energy [GeV] of primary (from the IP) particles at the TAN BLUE: total energy of particles per 1 p-p event BLUE: total energy of particles per 1 p-p event 7 TeV450 GeV

14. AVERAGE ENERGY AT THE TAN RED: average energy [GeV] of primary particles at the TAN RED: average energy [GeV] of primary particles at the TAN BLUE: energy of all particles per 1 p-p event BLUE: energy of all particles per 1 p-p event 7 TeV450 GeV

15. COMPARISON OF THE ESTIMATES Flux and spectra estimates are cross-checked with the existing data Flux and spectra estimates are cross-checked with 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 progress) EPICS: nice agreement at 7 TeV (450 GeV in progress) Particle spectra and average energy compared Particle spectra and average energy compared MARS: Good agreement on average quantities MARS: Good agreement on average quantities Total P[W@10 34 (8x10 8 p-p inelastic interaction/s)] = 168 vs. 164 (NM) Total P[W@10 34 (8x10 8 p-p inelastic interaction/s)] = 168 vs. 164 (NM) Factor ~2 difference in total multiplicity and average energy Factor ~2 difference in total multiplicity and average energy

16. HADRON FLUX AT THE TAN LEFT: DPMJET-FLUKA, RIGHT: LHC Report 633 hadron (with E>20 MeV) flux density at the TAN LEFT: DPMJET-FLUKA, RIGHT: LHC Report 633 hadron (with E>20 MeV) flux density at the TAN For the rate of 8  10 8 p-p inelastic interactions/s in IP5 For the rate of 8  10 8 p-p inelastic interactions/s in IP5 DPMJET+FLUKA2006.3

17. PARTICLE SPECTRA AT THE TAN LEFT: DPMJET-FLUKA, RIGHT: LHCf data by H.Menjo LEFT: DPMJET-FLUKA, RIGHT: LHCf data by H.Menjo For the rate of 8  108 p-p inelastic interactions/s in IP5 For the rate of 8  108 p-p inelastic interactions/s in IP5 DPMJET +FLUKA LHCf data 2x10 3 5x10 4 50 GeV 10 6

18. CONCLUSION DPMJET-FLUKA cascade simulation scheme established for the LSSs DPMJET-FLUKA cascade simulation scheme established for the LSSs Calculations for the particle flux and energy distribution for the forward detectors in the TAN performed for 7 TeV and 450 GeV operation Calculations for the particle flux and energy distribution for the forward detectors in the TAN performed for 7 TeV and 450 GeV operation The results checked with the existing data and found coherent The results checked with the existing data and found coherent The source files will be available for the analysis in the experimental groups The source files will be available for the analysis in the experimental groups

19. BACK-UP SLIDES

20. PARTICLE FLUX AT 450 GEV

21. PARTICLE FLUX AT 7 TEV

22. PARTICLE SPECTRA AT THE TAN 7 TeV450 GeV

23. COMPARISON WITH MARS (1) FROM IP (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

24. COMPARISON WITH MARS (2) TOTAL (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