IMPACT OF WATER OPTICAL PROPERTIES ON RECONSTRUCTION: HINTS FROM THE OB DATA. A PRELIMINARY STUDY ANTARES Collaboration Meeting CERN, February 07 th -10.

IMPACT OF WATER OPTICAL PROPERTIES IMPACT OF WATER OPTICAL PROPERTIES ON RECONSTRUCTION: HINTS FROM THE ON RECONSTRUCTION: HINTS FROM THE

OB DATA . A PRELIMINARY STUDYOB DATA . A PRELIMINARY STUDY

IMPACT OF WATER OPTICAL PROPERTIES IMPACT OF WATER OPTICAL PROPERTIES ON RECONSTRUCTION: HINTS FROM THE ON RECONSTRUCTION: HINTS FROM THE

OB DATA . A PRELIMINARY STUDYOB DATA . A PRELIMINARY STUDY

ANTARES Collaboration Meeting ANTARES Collaboration Meeting

CERN, February 07CERN, February 07thth-10-10thth, 2011, 2011

H Yepes -Ramirez H Yepes -Ramirez IFIC (CSIC – Universitat de València)IFIC (CSIC – Universitat de València)

OUTLINEOUTLINEOUTLINEOUTLINE

ANTARES Collaboration Meeting ANTARES Collaboration Meeting CERN, CERN, FebruaryFebruary 07 07thth-10-10thth2

Motivation of the study: Motivation of the study: hints from OB data

Brief reminder of light Brief reminder of light propagation in sea waterpropagation in sea water

Simulation: Simulation: inputs and codes

Preliminary resultsPreliminary results

Conclusions and outlookConclusions and outlook

Motivation of the study: Motivation of the study: hints from OB data

Brief reminder of light Brief reminder of light propagation in sea waterpropagation in sea water

Simulation: Simulation: inputs and codes

Preliminary resultsPreliminary results

Conclusions and outlookConclusions and outlook

MOTIVATION OF THE STUDYMOTIVATION OF THE STUDYMOTIVATION OF THE STUDYMOTIVATION OF THE STUDY

ANTARES Collaboration Meeting ANTARES Collaboration Meeting CERN, CERN, FebruaryFebruary 07 07thth-10-10thth3

HINTS FROM THE OPTICAL BEACON MEASUREMENTS FOR TRANSMISSION/ABSORPTION LENGTH:

• The transmission length procedure has given confidence to extract the absorption length using the “R” technique based on the information of the single scattering light, when the data/MC (CALIBOB) agreement will be checked.

• A preliminary value for the absorption length (abs = 63 m) was given to the collaboration under the constrains of the full data/MC (CALIBOB agreement) J Ruiz, “Extraction of the absorption length using the R technique”, ANTARES collaboration meeting in Paris. Several combinations (25) of optical parameters were used in order to find “the best” model which could be adapted to the real data:

• To resume old analysis, in particular A Margiotta, “Study of water properties on Monte Carlo simulation of the atmospheric muon flux”, ANTARES-SOFT-2007-006.

LIGHT PROPAGATION IN SEA LIGHT PROPAGATION IN SEA WATERWATER

LIGHT PROPAGATION IN SEA LIGHT PROPAGATION IN SEA WATERWATER

ANTARES Collaboration Meeting ANTARES Collaboration Meeting CERN, CERN, FebruaryFebruary 07 07thth-10-10thth4

Scattering phase function ()

Scattering angle distributionScattering angle distributionMolecular scattering (Rayleigh) Isotropic

= contribution of Rayleigh scattering.

Particle scattering (Mie) Strong forward peaked

effscatabs

effatt

111

cos1scateff

scat

Attenuation Length (COLIMATED BEAM)

Effective Attenuation Length (ISOTROPIC SOURCE)

Absorption length Scattering Length

scatabsatt 111

REMINDER OF LIGHT PROPAGATION IN SEA WATER:

Mie

scateffscat

cos)1(1

924.0cos Mie

Scattering length wavelength dependence

(Kopelevich parameterization)

][550

312.0550

34.1550

0017.0 13.07.13.4

mvvb ls

scat

b1

b = scattering coefficient.

vs, vl = scattering centers.

<Cos> = Average cosine of the global distribution

Petzold values for particle scattering

SIMULATIONSIMULATIONSIMULATIONSIMULATION

ANTARES Collaboration Meeting ANTARES Collaboration Meeting CERN, CERN, FebruaryFebruary 07 07thth-10-10thth5

SIMULATION INPUTS AND CODES:

A dedicated simulation was prepared taking into account our interest to see the influence of the water parameters in the MC:

1)Production of the absorption and scattering spectrum for different water models (12 runs in total):

SIMULATIONSIMULATIONSIMULATIONSIMULATION

ANTARES Collaboration Meeting ANTARES Collaboration Meeting CERN, CERN, FebruaryFebruary 07 07thth-10-10thth6

2) Six MC runs for different absorption length (55 m and 60 m):

• Three runs with the same value and different scattering spectrum.

• Three runs with different values, but is computed in such a way that the three runs will have the same effective scattering length at 470 nm.

• In total 10 runs are created:

3) Angular acceptance of June 2009 (Genova Meeting 2009).

4) MC production for neutrinos, not for atmospheric muons.

abs [m] Vs, vl (scattering centers) scat at 470 nm [m]

55 0.0075 53 0.17

55 0.01 41 0.17

55 0.02 22 0.17

55 0.01 41 0.11

55 0.02 22 0.02

63 0.0075 53 0.17

63 0.01 41 0.17

63 0.02 22 0.17

63 0.01 41 0.11

63 0.02 22 0.02

SIMULATIONSIMULATIONSIMULATIONSIMULATION

ANTARES Collaboration Meeting ANTARES Collaboration Meeting CERN, CERN, FebruaryFebruary 07 07thth-10-10thth7

5) Simulation chain:

GENGENWATER MODEL:

•Photon tables production (water tables) Water tables (hbook files) + Tables description (ASCII files).

HITHITOM PARAMETERS:

• Hit probability computation from the water tables for a given OM parameters Hit tables (hbook files) + Tables description (ASCII files).

KM3KM3SIMULATED EVENTS: GEOMETRY + KINEMATICS

• Physics events reading and OM hits production based on event geometry and hit probability tables Detector events: Signal hits (muons, not tracks from hadronic showers), physical background.

GEASIMGEASIM

MCEWMCEW

TETE

RECORECO

SIMULATIONS OF ATMOSPHERIC NEUTRINO INTERACTIONS.

• Process (and evaluation) tracks from particles coming from the hadronic showers (also muons from KM3).

TRANSLATION OF INFO ASCII FILES INTO ROOT FORMAT.

FORMAT CONVERSION TO “LOOK LIKE DATA”: electronics smearing effects (calibration, ARS response) and optical background.

RECONSTRUCTION: Reconstruction of track direction (AAfit) and ntuples information arrangement as number of hits, zenith distribution…(AntDST).

SIMULATIONSIMULATIONSIMULATIONSIMULATION

ANTARES Collaboration Meeting ANTARES Collaboration Meeting CERN, CERN, FebruaryFebruary 07 07thth-10-10thth8

5) Main options and software version in neutrino simulation:

6) Only reconstructed events will be shown, a systematic study from non-reconstructed events will be established since now. The purpose is just to have a first look on the influence of optical parameters!

CODE/INPUT OPTIONS/VERSIONS

GEN v3r7

HIT v3r7

KM3 v3r7

DETECTOR r12_c00_s01

GEASIM v4r10

MCEW

TriggerEfficiency Gaussian ARS threshold file: threshold_gaus_0.33_0.08_0.1.txt

ARS noise file: noiseblendL12-basic.root (Aart)

-n 10000000 –t 104.858 –C3 – p 0.035

-t 104.858 Frame time in ms. To determine the number of background hits to be generated in case the summary data are used.

-C3 Hit generator type: 3, Gaussian, according observed charge distribution, with time-dependent contribution of after pulses.

Aafit v0r6

AntDST v1r1

PRELIMINARY RESULTSPRELIMINARY RESULTSPRELIMINARY RESULTSPRELIMINARY RESULTS

ANTARES Collaboration Meeting ANTARES Collaboration Meeting CERN, CERN, FebruaryFebruary 07 07thth-10-10thth9

RECONSTRUCTION QUALITY PARAMETER ():

• The scattering length has a big influence on the lambda distribution, as seen when is fixed:

• Changing values for the contribution of Rayleigh scattering (), the scattering effects on have not an appreciable effect Combinations of and scat gives the same effective scattering length in the three cases. meff

scat 4.227

scat [m] 53 41 22

scat,eff [m] 227.4 175.9 94.4

PRELIMINARY RESULTSPRELIMINARY RESULTSPRELIMINARY RESULTSPRELIMINARY RESULTS

ANTARES Collaboration Meeting ANTARES Collaboration Meeting CERN, CERN, FebruaryFebruary 07 07thth-10-10thth10

RECONSTRUCTION QUALITY PARAMETER ():

• If the values for are kept as fix, with a reduced abs = 55 m, the impact of scat on , is not evident enough for < -5.

• At abs = 55 m, changing values for the contribution of Rayleigh scattering (), the scattering effects on have not an appreciable effect.

PRELIMINARY RESULTSPRELIMINARY RESULTSPRELIMINARY RESULTSPRELIMINARY RESULTS

ANTARES Collaboration Meeting ANTARES Collaboration Meeting CERN, CERN, FebruaryFebruary 07 07thth-10-10thth11

ZENITH ANGLE DISTRIBUTION:

• The most appreciable effects from neutrinos arriving in zenith direction are seen when the scattering length is low.

• If changes and effective scattering length is fixed, gives the same result for zenith distributions.

PRELIMINARY RESULTSPRELIMINARY RESULTSPRELIMINARY RESULTSPRELIMINARY RESULTS

ANTARES Collaboration Meeting ANTARES Collaboration Meeting CERN, CERN, FebruaryFebruary 07 07thth-10-10thth12

ZENITH ANGLE DISTRIBUTION:

• If the absorption length is low, there is not appreciable differences is and the effective scattering length are fixed or not.

CONCLUSIONS AND OUTLOOKCONCLUSIONS AND OUTLOOKCONCLUSIONS AND OUTLOOKCONCLUSIONS AND OUTLOOK

ANTARES Collaboration Meeting ANTARES Collaboration Meeting CERN, CERN, FebruaryFebruary 07 07thth-10-10thth13

1. Several MC productions using Partic Model have been performed in order to study the influence of the scattering in the reconstruction:

• The scattering effects are remarkable, but if and the scat is changed, and fixing one value for the effective scattering length at 470 nm, the differences on zenith and reconstruction quality parameter distributions are not so evident.

2. Present work is an ONGOING work, some cross-checks before and after the reconstruction will be review in detail and some priorities on physics analysis will be defined.

1. Several MC productions using Partic Model have been performed in order to study the influence of the scattering in the reconstruction:

• The scattering effects are remarkable, but if and the scat is changed, and fixing one value for the effective scattering length at 470 nm, the differences on zenith and reconstruction quality parameter distributions are not so evident.

2. Present work is an ONGOING work, some cross-checks before and after the reconstruction will be review in detail and some priorities on physics analysis will be defined.

BACKUPBACKUPBACKUPBACKUP

ANTARES Collaboration Meeting ANTARES Collaboration Meeting CERN, CERN, FebruaryFebruary 07 07thth-10-10thth14

5 parameters fit - 2 minimization: t0, , , x0, y0

cgctheory

k

v

kl

ctt

sin

1

tan

10

Reconstruction quality factor L:

• Linear prefit photon hit coordinates x, y, z, t

• Minimization with hit-charge weights.

• Maximum likelihood (L) fit computed from MC PDF of time residuals.

)1(log

solutionsdof

NN

L