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README
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20121225
Prob3++ is an Engine for computing three-flavor neutrino oscillation
probabilities. The main library libThreeProb.a can be used
to externally call routines to compute said probabilities.
////// Library Version
This document is valid for library version
v2.10
////// main library compilation
Makefile:
> make
Included in this module are two simple programs to give the user a general feel
for how the library works.
probLiner.cc:
Makefile
made with -> make probLinear
run with -> ./probLinear
This program will compute neutrino oscillations for neutrinos passing through
a slab of the constant density. The output file, LinearProb.root will contain
ROOT histograms of these probabilities as a function of density, L/E, and as functions
of L and E separately. The oscillation probabilities are set with the main body of the code.
probRoot.cc:
GNUmakefile (source appropriate env.csh)
made with -> make probRoot
run with -> ./probRoot
ProbRoot similarly computes oscillations but for neutrinos travelling through a sphere. The defualt
radial denisty profile is that of the Earth. However a density profile may be loaded from a text file
for a sphere of any denisty profile and radius. More will be discussed below. In this case oscillation
probabiliteies as a funciton of neutrino zenith angle, and energy are computed and dumped into
a file RawProb.root. The histograms therein can readily be viewed using makeOne.C
> root -l RawProb.root makeOne.C
///// About Parameter inputs
The software has been written assuming neutrino propagation in a normal
hierarchy. In this convention the atmospheric delta-m^2 is defined to be
a positive number for the normal hierarchy. The fundamental input mass squared
difference for atmospheric mixing is m^2_{32} = m^2_3 - m^2_2.
There are two modes of mixing which can be specified by a call to
BargerPropagator::SetOneMassScaleMode( bool ). The default mode
corresponds to true (this is also true if no call to this function is made)
In this mode, BargerPropagator::SetOneMassScaleMode( true )
* To compute oscillation probabilities assuming an inverted hierarchy
use a negative number for the value of delta-m^2. The code will
automatically adjust the input value by the solar mass splitting
to provide the correct value of m^2_{32} to internal routines. Effectively
the input mass squared splitting in this case corresponds to m^2_{31}
Under BargerPropagator::SetOneMassScaleMode( false )
* To compute oscillation probabilities assuming an inverted hierarchy
again use a negative number for the value of delta-m^2_32, but the
difference between normal hierarch and inverted hierarchy values
of this parameter must be specified by hand. That is, the correction
for the finite size of the solar splitting must be performed manually.
The MNS matrix is defined not only by the mixing parameters but
also by the expected type of progation, neutrino or antineutrino.
This produces an extra argument in the call to SetMNS (see below)
* To compute oscillation probabilities for antineutrinos
- Change the sign of the input neutrino flavor ( see below )
-- As of v2.00 it is no longer necessary to change the sign of dcp
during antineutrino propagation.
///// About propagators
There are a few "propagators" included in this module, all of which derive from the
NeutrinoPropagator class. The most commonly used one is the BargerPropagator.
The neutrino oscillation probabilities are stored as doubles.
Its use follows:
// create a pointer to a new BargerPropagator Object
BargerPropagator * bNu = new BargerPropagator( );
OR to use a user-defined density profile
BargerPropagator * bNu = new BargerPropagator( some-file-name );
// specify the neutrino oscillation parameters
// the form of the variables is interpreted by the last boolean, kSquared
// when true, it means that mixing angles, theta23, etc. are of the form sin^2( theta23 )
// when false, the mixing angles, are of the form sin^2(2 theta23 )
// Delta cp should be entered in radians
// The last parameter is +: neutrinos -:anti-neutrinos , defaults to neutrino
bNu->SetMNS( theta12, Theta13, Theta23, dm12, DM23, delta_cp , Energy, kSquared, KNuType );
*****
N.B. This routine reverses the sign of delta_cp for antineutrino propagation
to perform the complex conjugation of the MNS matrix internally.
Please note this behavior is different than earlier versions of the library ( <= v1.00 )
and the user is no longer responsible for changing the sign of delta_cp by hand.
If the neutrino type is not the same as that in the call to propagate (see below)
program execution stops.
This error can be suppressed with a call to
BargerPropagator::SetWarningSuppression()
For expert use only
*****
After the propagator has been created there is a choice of propagation modes
// to progagate through linear matter of constant density
// type is an integer, +: neutrino propagaton -: anti-neutrino propagation
// it should be the same as in the call to SetMNS (see above)
// PathLength is the pathlength through the matter in [km]
// Density is the matter's density in [g/cm^3]
bNu->propagateLinear( type, PathLength , Density );
OR
// to propagate through matter in a sphere:
// cosineZ is the neutrino zenith angle -1: upward going, 0: horizontal +1:downward going
// prod_height is the production height in the atmosphere [km]
// type is an integer, +: neutrino propagaton -: anti-neutrino propagation
bNu->DefinePath( cosineZ, prod_height );
bNu->propagate( type );
At this point the computed oscillation probabilities can be obtained with a call to:
// the neutrino types are:
// 1:e 2:mu 3:tau -1: e_bar -2: mu_bar -3: tau_bar
prob = bNu->GetProb( nu_in, nu_out );
OR
For Vacuum oscillation probabilities the situation is more straightforward
// Energy is [GeV]
// Path is [km]
prob = bNu->GetVacuumProb( nu_in, nu_out , Energy, Path );
Everytime a the energy or desired oscillation probabilities change one must call
the SetMNS() routine before calling one of the above three propagation routines.
If for instance these parameters are not changed, subsequent calls to the
propagation routines may be made _without_ another call to SetMNS().
/////// about input density profiles
User-specified density profiles must contain two columns of floating point
numbers, the first is the radial distance [km] from the sphere center, the second
is the density [g/cm^3] for
0. x_0
r_1 x_1
.. ..
r_n x_n
the last entry should contain the radius of the sphere.
each x_i represents the density up to and including r_i
the entry for zero radial density must be included.
so in PREM.dat, the lines
1220 13.0
3480 11.3
indicate that the density of the earth from 1220 to 3480 radial km
is 11.3 g/cm^3. ( Below 1220 km, is 13.0 g/cm^3 )
//////////
///////////// About
This code has been written by members of the Super-Kamiokande collaboration
and is presented here in a purified form. Though not the sole author,
Roger Wendell (-rvw) is presently maintaining the software. Comments and suggestions
are welcome at:
Other types of oscillation modules may be provided in the future. Thanks kindly,
and please enjoy your personal search for cp violation!