Hadroproduction data parameterisations for fast neutrino beams calculations

1. NuFact 05 Hadroproduction data parameterisations for fast neutrino beams calculations M. Bonesini Sezione INFN Milano Dipartimento di Fisica G. Occhialini Universita’ di Milano-Bicocca M. Bonesini -NUFACT05

2. Conventional nm beams (from p decay) WANF • Problem in conventional beams: a lot of minority components -> needs better knowledge of sec. production in target Exp. Decay Pipe Hadron m+ p+ n p Absorb. Target Rock Horns M. Bonesini -NUFACT05

3. Simulation of neutrino beams 1. Primary target production 2. re-interactions in target 3. re-interactions in beamline Full Montecarlo simulation (MARS, FLUKA, Geant 3 or 4) Good for study of systematics Fast simulation (parametrization of hadron production data, re-int models) Good for beamline optimization M. Bonesini -NUFACT05

4. Some examples BMPT fast simulation: CHARM II Both points to good hadron production data Fluka full simulation (+ reweighting with SPY data): WANF for NOMAD M. Bonesini -NUFACT05

5. Low Energy data: Harp is coming • 2-15 GeV/c incident p beam on nuclear targets (Be, C,Al, Cu, Sn, Ta, Pb, ... + Miniboone & K2K replica) • Full solid angle acceptance • PID for p/p separation Aims: cross sections at a 2% precision See E. Radicioni talk for details (thin Al target results) Some old datasets: • J. Allaby et al., CERN-70-12 • G. Eichten et al.,Nucl. Phys. B44(1972) 333 • All datasets useful, but suffer from low statistics and high systematics (15 % on cross sections) M. Bonesini -NUFACT05

6. K2K: Al MiniBoone: Be LSND: H2O 5% 50% 100% Replica 5% 50% 100% Replica 10% 100% +12.9 GeV/c +8.9 GeV/c +1.5 GeV/c Data taking summary HARP took data at the CERN PS T9 beamline in 2001-2002 Total: 420 M events, ~300 settings SOLID targets:  EXP replica target: CRYOGENIC targets: M. Bonesini -NUFACT05

7. Higher energy data • Barton et al., Phys. ReV. D27(1983),2580 • Study of inclusive production of p, K, p, pbar in 100 GeV/c p+,K+,p collisions with C,Al,Cu,Ag,Pb targets • Single arm M6E Fermilab spectrometer • Skubic et al., Phys. ReV. D18 (1978), 3115 • Strange particle production in 300 GeV/c p collisions with Be,Cu,Pb • H.W. Atherton et al. (NA20), CERN 80-07, 1980 • p = 60, 120, 200, 300 GeV/c; pt = 0, 500 MeV/c • target plate length = 40, 100, 300, 500 mm • G. Ambrosini et al. (NA56/SPY), Eur. Phys. J. C10 (1999) 605 • p = 7, 10, 15, 20, 30, 40, 67.5, 135 GeV/c (at pt = 0); pt = 0, ±75, ±150, ±225, ±337, ±450, +600 MeV/c (for p = ±15, ±40 GeV) • target plate length = 100, 200, 300 mm • WANF “T9-like” target (3 rods 10 cm long, 3 mm thick) M. Bonesini -NUFACT05

8. The Na56/SPY experiment • Measure p, kaon fluxes by 450 GeV/c p on Be ( 5% precision) ->knowledge of neutrino spectra • Measure k/p ratio (3% precision) -> knowledge ne/nm ratio • Equipped H6 beamline from NA52 experiment in North Area • Primary p flux measured by SEM • Different Be targets (shapes, L) • PID by TOF counters (low momenta) and Cerenkov (high momenta) • Critical points for such an experiment • beamline simulation (spectrometer acceptance) (5 – 10 % precision) • Particle misidentification ( < 1%) • Subtraction of long lifetime particles decaying outside the target (K0s -> pp, ...) (< 2%) • Beam momentum determination and K lifetime->uncertainty on K decay correction (1 %) • Protons on target (2 %) M. Bonesini -NUFACT05

9. Some NA56/SPY results: the K/p ratio • Solid points negatives, open points positives • Errors 3 % • K content (depleted by decays) enriched by trigger prescaling • 2 samples (one trigger natural composition, the other heavy particles K,p,..) • K/p=(K/p)heavy sample(p/p)natural M. Bonesini -NUFACT05

10. Some NA56/SPY results:p/K/pinclusive invariant cross sections • Forward invariant cross sections • Model independent extrapolation to zero target thickness with data itself (L=100,200, 300 mm targets) • Total error 10% M. Bonesini -NUFACT05

11. Low Energy: The Sanford-Wang Parameterization • Empirical parameterization with 8 free parameters: where: Pπ is the pion momentum. Pp is the incident proton momentum. Θπ is the pion production angle in the lab frame. c1-8 are the fit parameters Original S-W M. Bonesini -NUFACT05

12. S-W Fit Results • Available S-W fits for p-Be (usually made with a compilation of data): • Original S-W fit • Modified Cho S-W fit • K2K S-W fit • … • For p-Al 12.9 GeV/c new S-W fit from Harp data is coming From Mc-Gregor talk at NBI03 M. Bonesini -NUFACT05

13. Comparisons Cho et al. data Marmer et al. data From Mc-Gregor talk at NBI03 M. Bonesini -NUFACT05

14. DRAFT DRAFT HARP preliminary S-W fit to p-Al data at 12.9 GeV/c • small statistical and syst errors • data compatible with older ones • Useful for understanding of K2K beamline M. Bonesini -NUFACT05

15. The existing parameterizations of secondary particle yield at higher energy • Simple formulas fitting the yield of charged secondary particles from 400 GeV/c protons on Be targets: • Data above 60 GeV/c (x ≈ 0.15) at pt = 0 and 500 MeV/c • H.W. Atherton et al., CERN 80-07, 1980: thin target approximation • A.J. Malensek, FN-341,1981: thick target approximation (500 mm) • Both fail at low x M. Bonesini -NUFACT05

16. A new parameterization of secondary particle yield from thick targets: the BMPT parametrization • Goal: improvement with respect to previous models at low x (and pT  0).H.W. Atherton et al., CERN 80-07, 1980, A.J. Malensek, FN-341,1981 • Secondary yield from fit of: • p+ and K+ invariant cross-section data derived from Atherton et al. & NA56/SPY Collaboration data (Be target), • p–/ p+ and K–/K+ data • K0L evaluation from simple parton model. • Evaluation of tertiary particles production: • Comparison of secondary production from targets of different thickness (100, 200, 300 mm and T9) in Na56/SPY. • Extrapolation to other target material and incident p energy: M. Bonesini -NUFACT05

17. The invariant cross section for p+ and K+ • Empirical formula based on general physical arguments. • Approximate factorization in x and pt • (1-x)a behavior in the forward direction for x 1 (quark counting rule) • x-b behavior in for x 0 (non direct hadron formation mechanism ) • Exponential fall in pt for soft interaction • xR=E*/E*max (greatly extends scaling to sub-asymptotic energies, Yen Phys. ReV. D10 (1974) 836) M. Bonesini -NUFACT05

18. The invariant cross section for p-, K- and K0L • Empirical formula describing p+/p- and K+/K- ratios: • function of x only • R(p) and R(K) shapes supported by analysis of pp data by Ochs (Nucl. Phys. B118 (1977) 397) • R(p)  1 for x  0; R(p)  5 for x  1; • R(K) (1-x)-3 for x  1; • K0L production evaluated from simple parton model (n = u/d ≈ 2 assuming isospin symmetry) M. Bonesini -NUFACT05

19. Invariant cross sections: a) pions, b) kaons M. Bonesini -NUFACT05

20. Parametrization extrapolations • Extension to other target material: • Known dependence of the invariant cross section on atomic number A: • From data on several nuclei: a(x) ≈ (0.74- 0.55 x + 0.26 x2)).(0.98+0.21 p2T) (D.S. Barton et al., Phys. Rev. D35 (1987) 35, Skubic et al., Phys. ReV. D18(1978) 3115) ≤ 5% systematic error from Be to C • Comparison with data at different incident proton energy: • 100 GeV/c proton on Carbon(D.S. Barton et al., Phys. Rev. D27 (1983) 2580) • 24 GeV/c proton on Beryllium(T.Eichten et al., Nucl. Phys. B44 (1972) 333) M. Bonesini -NUFACT05

21. Comparison of BMPT with other energies Eichten et al. (24 GeV/c) Barton et al. (100 GeV/c) Courtesy of A. Marchionni M. Bonesini -NUFACT05

22. Empirical model for tertiary particles production on thick targets (SPY data) • Experimental evidences: • Comparison of secondary production from targets of different thickness (100, 200, 300 mm and T9) in SPY • Naive absorption model inadequate at large thicknes • Empirical assumptions (for long “needle-like” targets): • Tertiary particles produced mostly by re-interaction of leading secondary particle in the forward direction -> model to reproduce NA56/SPY data M. Bonesini -NUFACT05

23. A fast neutrino beam simulation (based on BMPT parametrization) • Secondary meson production from BMPT parametrization • 3-dimensional description of all beamline elements • Tracking of parent mesons • Neutrino production from parent meson decay (2/3 body decay included) • Useful to check parametrization, fast simulation tool to “debug” beamlines M. Bonesini -NUFACT05

24. A fast neutrino beam simulation:phase-space weighting Hadron decay probability inside the tunnel Interact. in material 2/3 body decay branching ratio Probability that the n is emitted in the detector direction n momentum in lab frame Solid angle Total n cross-section Nucleon target density in the detector Focusing Decay tunnel L devices det R det q Target nh Z L det h L h,MAX M. Bonesini -NUFACT05

25. An application to WANF: Proton int in target p+ p– • 450 GeV protons • Beryllium target • 30 mrad acceptance • Exit point from target: • Black: Fluka • Blue: Secondaries only • Red: with Tertiaries K+ K- M. Bonesini -NUFACT05

26. 450 GeV p on Be target 30 mrad acceptance p,pT secondary mesons from target WANF: proton interactions in target p+ K+ p+ K+ M. Bonesini -NUFACT05

27. WANF: Comparison with CHARM II data The CHARM II collab., Eur. Phys. J. C11 (1999), 18 • 450 GeV p on Be • 8 mrad acceptance • Detector at 881 m • Positive focusing • nm beam (105 pot) • CHARM II data • Anti- nm contamination M. Bonesini -NUFACT05

28. WANF:comparison with CHARM II data The CHARM II collab., Eur. Phys. J. C11 (1999), 18 • 450 GeV p on Be • 8 mrad acceptance • Detector at 881 m • Negative focusing • CHARM II data • Anti-nm beam (105 pot) • nmcontamination M. Bonesini -NUFACT05

29. An application to CNGS: Comp with Fluka+Geant MC R. Bailey et al., CERN-SL-99-034-DI, 1999 • 400 GeV protons on graphite target • Positive focusing • Detector at 732 Km • This simulation • Fluka+Geant MC M. Bonesini -NUFACT05

30. An application to NUMI (from M. Messier et al.) • Comparison BMPT, Mars, GFLUKA in Minos near/far detecor M. Bonesini -NUFACT05

31. An off-axis calculation (from S. Wojcicki) • Physics potential of different sites for NuMI off-axis detector in term of FOM=S/sqrt(B) • Fast simulation based on BMPT (3Kevt/s on a laptop) Dm13= x10-3 eV2 M. Bonesini -NUFACT05

32. Conclusions • Full or fast simulation need good quality hadroproduction data in the forward direction: call it parametrization or reweighting … • Parametrization of available high-energy data on particle production on light nuclei (BMPT): • Fits satisfactory the 400 & 450 GeV p-Be experimental data over a wide x and pT range. • Can be safely extrapolated to thick target and to different proton momentum (≈ 24 GeV/c) and target material: we will check soon with HARP data down to 8-10 GeV/c • Can be applied to neutrino beam simulations: • Efficient (fast) alternative to full hadronic cascade codes • Reproduces existing data within ≈ 10% (CHARM II and ...) M. Bonesini -NUFACT05

33. Many thanks to F. Pietropaolo,T. Tabarelli and A. Marchionni with whom most of this work was done in some old and happy days Acknowledgements M. Bonesini -NUFACT05