Kevin McFarland, “ and , oh my” 1 5 July 2002 The Delicate Minutia of Fluxes, Neutrino...

Kevin McFarland, “Kevin McFarland, “andand, oh , oh my”my” 11 5 July 20025 July 2002

The Delicate Minutia of The Delicate Minutia of Fluxes, Neutrino Cross-Fluxes, Neutrino Cross-

Sections, and Detectors Near Sections, and Detectors Near and Far:and Far:

Kevin McFarlandKevin McFarlandUniversity of RochesterUniversity of Rochester

5 July 20025 July 2002For Working Groups 2 and 3For Working Groups 2 and 3

A Global PerspectiveA Global Perspective

22 5 July 20025 July 2002 Kevin McFarland, “Kevin McFarland, “andand, oh , oh

my”my”

OutlineOutline

• Why is this important?Why is this important?– Short-term expediencyShort-term expediency– Grand GoalsGrand Goals

• The bad newsThe bad news– The sub-few GeV region isn’t so easy!The sub-few GeV region isn’t so easy!– Cross-sections, detector effectsCross-sections, detector effects

• The good newsThe good news– Pioneers blazing the trailPioneers blazing the trail– Great toolbox: detectors, modelsGreat toolbox: detectors, models


my”my”

The Importance of The Importance of SuperbeamsSuperbeams• Low-energy beams are in our futureLow-energy beams are in our future

– BooNE BooNE (Coney)(Coney)

– NUMI beam: LE, ME off-axis NUMI beam: LE, ME off-axis (Szleper)(Szleper)

On-AxisOff-Axis


my”my”

Importance of Superbeams Importance of Superbeams (cont’d)(cont’d)

– JHF JHF (Kajita)(Kajita)

Num

ber

of e

vent

s /1

00M

eV/y

r

Eν(GeV)

Max. osc.

Background


my”my”

What Role do Low Energy What Role do Low Energy Beams Play in The Long-Term Beams Play in The Long-Term Future?Future?• Show non-zero UShow non-zero Ue3 e3

• Measure Measure mm222323

• Resolve DegeneraciesResolve Degeneracies– Even with a neutrino factory, archival Even with a neutrino factory, archival

superbeam measurements are key!superbeam measurements are key! (Minakata, (Minakata, Whisnant, Mena, Huber)Whisnant, Mena, Huber)

P(osc) vs E


my”my”

The Landscape of The Landscape of SuperbeamsSuperbeams• Can’t support L too largeCan’t support L too large

– Limited proton powerLimited proton power– No acceleration of neutrino source (à la No acceleration of neutrino source (à la ))

• Small L/E makes no senseSmall L/E makes no sense– Destroys degeneracy lifting propertyDestroys degeneracy lifting property– Backgrounds are too large to reduce P(osc)Backgrounds are too large to reduce P(osc)

•E.g., E.g., ee background is “naturally” ~1%; clever background is “naturally” ~1%; clever design can reduce this x2 or maybe x5…design can reduce this x2 or maybe x5…

• So ESo E is going to be sub-GeV to few-GeV is going to be sub-GeV to few-GeV


my”my”

And what’s so bad about And what’s so bad about that?that?

• EE~m~mtargettarget (Casper, Bodek)(Casper, Bodek)

– Massless quark DIS isn’t a good modelMassless quark DIS isn’t a good model– Have to deal with discrete final state massHave to deal with discrete final state mass– Center of mass not ultra-relativisticCenter of mass not ultra-relativistic

•Final state particles in every direction!Final state particles in every direction!

• Current data at low ECurrent data at low E stinks stinks– Who would work here if they had a choice?Who would work here if they had a choice?


my”my”

State of the art at low EState of the art at low E

n–p0

n–n+

p–p+

• Data at first resonance Data at first resonance (Casper)(Casper)– 20-50% uncertainties are par for course20-50% uncertainties are par for course– Relevant? >50% of K2K far spectrum sample is inelastic…Relevant? >50% of K2K far spectrum sample is inelastic…


my”my”

Can DIS describe Can DIS describe resonances?resonances?• Transition between resonance/DIS a Transition between resonance/DIS a

“twilight zone” for cross-sections“twilight zone” for cross-sections– Enter duality! Enter duality! (Bodek)(Bodek)

• ““If you get near a resonance, If you get near a resonance, it just sucks you in!”it just sucks you in!”

• Can model resonances Can model resonances using DIS cross-sections using DIS cross-sections with appropriate scalingwith appropriate scaling– Predictive approachPredictive approach– Should give a baseline to Should give a baseline to

measure (nuclear) measure (nuclear) deviationsdeviations


my”my”

Nuclear Cross-Section Nuclear Cross-Section EffectsEffects• Couple detector and cross-sectionCouple detector and cross-section• Many inaccurately modeled effects Many inaccurately modeled effects

(Casper)(Casper)

– E.g., quasi-elastic case, which is a calculable E.g., quasi-elastic case, which is a calculable cross-section, mcross-section, mAA=1.01±0.02 GeV=1.01±0.02 GeV

– Nuclear effects introduce uncertaintiesNuclear effects introduce uncertainties•Fermi motion, binding energy, Pauli blockingFermi motion, binding energy, Pauli blocking

•Final state interactionsFinal state interactions– Complicated even in quasi-elastic case; worse in Complicated even in quasi-elastic case; worse in

inelasticinelastic


my”my”

Far detectors at Low EFar detectors at Low E

• Water-Water-ЧеренковЧеренков (not named for a Čzech!!) (not named for a Čzech!!) (Yoshida, Campanelli, Kobayashi, Kajita)(Yoshida, Campanelli, Kobayashi, Kajita)

– Only sees particles over Only sees particles over ЧЧ threshold; may miss inelastics threshold; may miss inelastics– Very good low energy Very good low energy 00 detection detection

A test of reconstructio

n!

(Casper)

proton

: muon angle

p: muon momentum

quasi-elastic reconstruction

(See also Campanelli

on improvement

s)


my”my”

Far detectors at Low EFar detectors at Low E (cont’d)(cont’d)• Sampling Calorimeter at 2 GeV Sampling Calorimeter at 2 GeV (Para)(Para)

– Low Z, frequent sampling gives good E resolutionLow Z, frequent sampling gives good E resolution– 00(or other NC)/e(or other NC)/e-- separation can be achieved separation can be achieved

e-


my”my”

Far detectors at Low EFar detectors at Low E (cont’d)(cont’d)• Liquid Argon on the cheap? Liquid Argon on the cheap? (Cline, McDonald)(Cline, McDonald)

– We hold the following truth to be self-evident: that event We hold the following truth to be self-evident: that event reconstruction in Liquid Argon is outstanding reconstruction in Liquid Argon is outstanding (happy July 4(happy July 4thth!)!)

– ICARUS T600 analysis underwayICARUS T600 analysis underway

e-


my”my”

Beam Flux MonitoringBeam Flux Monitoring• BooNE BooNE (Coney)(Coney)

– problem is monitoring problem is monitoring ee sources ( sources (, K, K++))

Little Counter

s


my”my”

Beam Flux Monitoring Beam Flux Monitoring (cont’d)(cont’d)• NUMI Gedanken Flux NUMI Gedanken Flux (Szleper)(Szleper)

– transform near to far flux, even off-axistransform near to far flux, even off-axis

• A bottle of Sake is at stake…A bottle of Sake is at stake…– Para predicts that applied to K2K, error goes to 1%Para predicts that applied to K2K, error goes to 1%


my”my”

Beam Flux Monitoring Beam Flux Monitoring (cont’d)(cont’d)• K2K… champions of low E flux K2K… champions of low E flux

(Kobayashi)(Kobayashi)

– detailed check with pion monitor systemdetailed check with pion monitor system(beautiful talk… but I lost the slides! Sorry!)(beautiful talk… but I lost the slides! Sorry!)

– allows for energy dependent flux allows for energy dependent flux extraction by monitoring secondary extraction by monitoring secondary beambeam

• External data plays External data plays

an important rolean important role– HARP will help!HARP will help!

drift chambers

cherenkov

TOF wall electronidentifier

spectrometermagnet

TPC/RPC solenoidmagnet

forward triggerforward RPC

muonidentifier

“characterized” beam


my”my”

Near DetectorsNear Detectors• Two types of near detector systemsTwo types of near detector systems

– Mimic far detector as closely as possibleMimic far detector as closely as possible•study detector responsestudy detector response

•near/far ratio testnear/far ratio test

– Build a detector capable of measuring Build a detector capable of measuring details of neutrino interactionsdetails of neutrino interactions•cross-section studiescross-section studies

• Nuclear effects may eventually Nuclear effects may eventually require us to merge these functions!require us to merge these functions!


my”my”

Near Detectors (cont’d)Near Detectors (cont’d)• NUMI NUMI (Morfin)(Morfin)

– Strategy here is to mimic far detectorStrategy here is to mimic far detector– Also contemplating a cross-section detector Also contemplating a cross-section detector

for high energy cross-section studiesfor high energy cross-section studies

2.0 m x 2.0 m x 2.0 m long

Scintillator Only

Scint. + Planes of C, Fe,W

Upstream Half

Downstream Half


my”my”

Near Detectors (cont’d)Near Detectors (cont’d)• K2K has a near detector complex! K2K has a near detector complex! (Kajita)(Kajita)

– muon range for beam position (high mass)muon range for beam position (high mass)– 1kTon H2O-1kTon H2O-ЧЧ for near/far ratio for near/far ratio– Sci-Fi for cross-section studiesSci-Fi for cross-section studies

flux anddirection


my”my”

Near Detectors (cont’d)Near Detectors (cont’d)• K2K fine-grained detector upgrade K2K fine-grained detector upgrade

(Kajita)(Kajita)

– full QE reconstruction to low pfull QE reconstruction to low ppp!!

Monte Carlo


my”my”

Near Detectors (cont’d)Near Detectors (cont’d)• JHF2K plans inherit from K2K JHF2K plans inherit from K2K (Kajita)(Kajita)

– 280m (cross-section, position) detector280m (cross-section, position) detector– 2km near/far detector2km near/far detector

ν

15.2m

8m

4m


my”my”

Near Detectors (finally…)Near Detectors (finally…)• NUMI 0.7NUMI 0.7oo

OA may also be able to OA may also be able to accommodate a near OA detectoraccommodate a near OA detector– 2 GeV cross-sections, NUMI OA flux2 GeV cross-sections, NUMI OA flux– EOI to FNAL PAC; could run in 2005EOI to FNAL PAC; could run in 2005


my”my”

ConclusionsConclusions

• At NuFact09, we will…At NuFact09, we will…

• Low Energy Superbeams likely require:Low Energy Superbeams likely require:– Detailed attention to cross-section, fluxDetailed attention to cross-section, flux– Systems of near detectors, beam monitorsSystems of near detectors, beam monitors

•Supporting production, cross-section experiments?Supporting production, cross-section experiments?

Learn that the uncertainty on (

12C->11C+n+0)

limits our knowledge of 13, ?

Pat ourselves on the back for measuring cross-sections,

fluxes and detector response!

Find the e component of our anti-neutrino beam was twice as high as

we thought… but just wait ‘til NuFact19!

Kevin McFarland, “ and , oh my” 1 5 July 2002 The Delicate Minutia of Fluxes, Neutrino...

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