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NuFact 05. Hadroproduction data parameterisations for fast neutrino beams calculations. M. Bonesini Sezione INFN Milano Dipartimento di Fisica G. Occhialini Universita’ di Milano-Bicocca. Conventional n m beams (from p decay). WANF. - PowerPoint PPT Presentation
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M. Bonesini -NUFACT05 1
Hadroproduction data parameterisations for fast
neutrino beams calculations
M. BonesiniSezione INFN Milano
Dipartimento di Fisica G. OcchialiniUniversita’ di Milano-Bicocca
M. Bonesini -NUFACT05 2
Conventional beams (from decay)
p+
Exp.
Decay Pipe
+
Rock
Hadron
Absorb.
Horns
Target
Problem in conventional beams: a lot of minority components -> needs better knowledge of sec. production in target
WANF
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)
Fast simulation (parametrization of hadron production data, re-int models)
Good for beamline optimization
Good for study of systematics
M. Bonesini -NUFACT05 4
Some examples
Fluka full simulation (+ reweighting with SPY data): WANF for NOMAD
BMPT fast simulation: CHARM II
Both points to goodhadron production data
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 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
+1.5 GeV/c
10%100%
LSND: H2O
+8.9 GeV/c+12.9 GeV/c
5%50%
100%Replica
5%50%
100%Replica
MiniBoone: BeK2K: Al
SOLID targets:
CRYOGENIC targets: EXP replica target:
HARP took data at the CERN PS T9 beamline in 2001-2002 Total: 420 M events, ~300 settings
Data taking summary
M. Bonesini -NUFACT05 7
Higher energy data Barton et al., Phys. ReV. D27(1983),2580
Study of inclusive production of , K, p, pbar in 100 GeV/c ,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 , kaon fluxes by 450 GeV/c p on Be ( 5% precision)
->knowledge of neutrino spectra Measure k/ ratio (3% precision) ->
knowledge e/ 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 -> ...) (< 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/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)heavy sample(p/natural
M. Bonesini -NUFACT05 10
Some NA56/SPY resultsK/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
)cos(
1
2 8765
43
2 )1(
cpc
pP
cPc
PcPc
p
c eP
PPc
dpd
d
• 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.
dataFrom Mc-Gregor talk at NBI03
M. Bonesini -NUFACT05 14
HARP preliminary S-W fit to p-Al data at 12.9 GeV/c
DRAFT
DRAFT
• 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
)51()1(
)1(422
2
Dx
t
A
Be eMp
xBx
ddp
Nd
)2
2)((
22max
2tCpBxBe ex
CBeAp
ddp
Nd
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: + and K+ invariant cross-section data derived from Atherton et
al. & NA56/SPY Collaboration data (Be target), –/ + and K–/K+ data K0
L 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 + and K+ Empirical formula based on general physical
arguments.
Approximate factorization in x and pt
(1-x) behavior in the forward direction for x 1 (quark counting rule)
x 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)
βR
)xR
Bx(1
)t
pγ
Rx
a(
e
)2t
pδ
R2x
2at
pγ
Rx
a(1α)
RxA(1
Be)
3dp
σ3d(E
M. Bonesini -NUFACT05 18
The invariant cross section for -, K- and K0
L
Empirical formula describing +/- and K+/K- ratios:
function of x only R() and R(K) shapes supported by analysis of pp data
by Ochs (Nucl. Phys. B118 (1977) 397)
R() 1 for x 0; R() 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)
))3N(K)(N(K4
1
2n
)1)N(K(2n)N(K)N(K 0
L
r1
R0
r1
R0 )x(1rR(K);)x(1rR(π(
M. Bonesini -NUFACT05 19
Invariant cross sections: Invariant cross sections: a) pions, b) kaonsa) 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: (x) ≈ (0.74- 0.55 x + 0.26 x2)).( 0.98+0.21 p2
T)
(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)
(E
d3dp3
)A1(
A1
A2
) (Ed3dp3
)A2
M. Bonesini -NUFACT05 21
Comparison of BMPT with other energies
Courtesy of A. Marchionni
Eichten et al. (24 GeV/c)
Barton et al. (100 GeV/c)
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
Zdet
Rdet
Ldet
Decay tunnel
h
Focusingdevices
Target
Lh
Lh,MAX
P (1 e
Lh ,MAX
h )e
Lh
h
e
Lmat
int
BR ex
(
mh
E h ph cosh
)2
0
mh2 m,x
2
2mh
mh
E h ph cosh
Rdet2
4Z det2
N AdetLdet
Interact. in
material
2/3 body decay
branching ratio
Probability that the is emitted in
the detector direction
Total cross-section
momentum in lab frame
Solid angle Nucleon
target density in
the detector
M. Bonesini -NUFACT05 25
An application to WANF: Proton int in target
450 GeV protonsBeryllium target30 mrad acceptance
Exit point from target:Black: FlukaBlue: Secondaries onlyRed: with Tertiaries
+ –
K+ K-
M. Bonesini -NUFACT05 26
WANF: proton interactions in target
450 GeV p on Be target
30 mrad acceptance
p,pT secondary mesons from target
+
+
K+
K+
M. Bonesini -NUFACT05 27
WANF: Comparison with CHARM II data
450 GeV p on Be
8 mrad acceptance
Detector at 881 m Positive focusing
beam (105 pot) CHARM II data Anti-
contamination
The CHARM II collab., Eur. Phys. J. C11 (1999), 18
M. Bonesini -NUFACT05 28
WANF:comparison with CHARM II data
450 GeV p on Be 8 mrad acceptance Detector at 881 m Negative focusing
CHARM II data Anti- beam (105
pot) contamination
The CHARM II collab., Eur. Phys. J. C11 (1999), 18
M. Bonesini -NUFACT05 29
An application to CNGS: Comp with Fluka+Geant MC
400 GeV protons on graphite target
Positive focusing Detector at 732
Km This simulation Fluka+Geant MC
R. Bailey et al., CERN-SL-99-034-DI, 1999
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)
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
2 2.5 3
LTVBuyckFort FrancesKenora
m13= 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