hadroproduction data parameterisations for fast neutrino beams calculations
DESCRIPTION
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 PresentationTRANSCRIPT
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
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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
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Some examples
Fluka full simulation (+ reweighting with SPY data): WANF for NOMAD
BMPT fast simulation: CHARM II
Both points to goodhadron production data
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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)
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+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
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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)
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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 %)
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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
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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%
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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
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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
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Comparisons
Cho et al. data Marmer et al.
dataFrom Mc-Gregor talk at NBI03
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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
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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
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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:
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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
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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(
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Invariant cross sections: Invariant cross sections: a) pions, b) kaonsa) pions, b) kaons
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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
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Comparison of BMPT with other energies
Courtesy of A. Marchionni
Eichten et al. (24 GeV/c)
Barton et al. (100 GeV/c)
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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
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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
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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
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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-
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WANF: proton interactions in target
450 GeV p on Be target
30 mrad acceptance
p,pT secondary mesons from target
+
+
K+
K+
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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
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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
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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
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An application to NUMI (from M. Messier et al.)
Comparison BMPT, Mars, GFLUKA in Minos near/far detecor
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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
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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 ...)
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Many thanks to F. Pietropaolo,T. Tabarelli and A. Marchionni with
whom most of this work was done in some old and happy days