[PPT] - Status and Perspectives of Short Baseline Studies Mark Dierckxsens PowerPoint Presentation

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Status and Perspectives

f Short Baseline Studies

TAUP 2009 July 1-5, 2009 Mark Dierckxsens University of Chicago

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Mark Dierckxsens TAUP 2009, July 1-5 2009

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Neutrino Oscillations

Pontecorvo-Maki- Nakagawa-Sakata Matrix:



e   = U e1 U e 2 U e3 U 1 U 2 U 3 U 1 U 2 U 3 1 2 3

U = cos12 sin12 −sin 12 cos12 1 cos13 sin 13e

−i

1 −sin 13e

i

cos13  1 cos23 sin 23 −sin 23 cos23

3 mixing angles 1 CP phase

⇨

(2 CP Majorana phases)

Many experiments (almost) all show consistent picture

atmospheric solar

12 ≈ 34

m21

2 ≈ 7.7 10 −5eV 2

23 ≈ 45

∣m31

2 ∣ ≈ 2.4 10 −3eV 2

θ13 < 11o (90%CL)

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Mark Dierckxsens TAUP 2009, July 1-5 2009

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Neutrino Oscillations

m31

2  0

m31

2  0

m21

2

sin2θ13: e in 3

Fogli et al arXiv:0905.3549

First hints of non-zero θ13?
Reactor neutrino

experiments under construction will be probing well into this region

combination of all neutrino data sin22θ13 = 0.08

Unknowns of neutrino
scillations:
θ13?
δcp?
mass hierarchy?

See talk A. Palazzo

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Mark Dierckxsens TAUP 2009, July 1-5 2009

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Measuring θ13 at reactors

P  e   e ≈ 1 − sin

2213sin 2 1.27 Lm31 2

E  − cos

413sin 2212sin 2 1.27 Lm21 2

E 

Measure survival probability of e from nuclear reactor:
for Eν = 4 MeV:

1st maximum at ~2km (@ Δm31

2=2.5 10-3 eV2)

Clean measurement of θ13:
weak dependance on

solar parameters at low L/E

no CP effects
negligible matter effects

subdominant θ13 oscillation dominant θ12 oscillation

L in m, E in MeV Δm2 in eV2

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Mark Dierckxsens TAUP 2009, July 1-5 2009

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Previous Experiments

Many reactor experiments at various distances

KamLAND PRL 90, 021802(2003)

  e   x

Δm2 (eV2) sin22θ

sin22θ13 < 0.16 (90% CL)

PRD 64:112001(2001)

CHOOZ Experiment

PL B466:415-430 (1999)

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Mark Dierckxsens TAUP 2009, July 1-5 2009

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Improving CHOOZ

CHOOZ Error on R=obs/exp Statistical Systematic 2.7% 2.8%

Larger detector
Longer running time
More powerful

reactors

Identical detector close to reactor:
ratio measurement eliminates

cross section, neutrino flux & some detector uncertainties

Improved detector design:
lower threshold, better efficiencies,

detailed calibration program

Lower background:
better veto, shielding, overburden

& radio-purity increase statistics reduce systematics

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Mark Dierckxsens TAUP 2009, July 1-5 2009

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Experiments Under Construction

Experiment Power (GWth) Distance N/F (m) Target N/F (t) Double Chooz

8.6 400/1050

8.6/8.6 RENO 17.3 290/1380 16/16

Daya Bay

11.6 (17.4) 360(500)/ 1990(2620) 2x40/80

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Mark Dierckxsens TAUP 2009, July 1-5 2009

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Neutrinos from Reactors

3.6 GWth

Isotropic & pure source
f ~2 1020 νe/GWth/s
νe produced through beta

decays of fission products

νe spectrum from measured β spectrum

K. Schreckenbach et al., PL B 160 (1985) 325 ;

A.A. Hahn et al., PL B 218 (1989) 365.

β spectrum from 235U, 239/241Pu

measured to 1.8%

Conversion results in error of 2.5-4%
Improved conversion calculations

and planned measurement of 238U will improve uncertainty

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Mark Dierckxsens TAUP 2009, July 1-5 2009

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Detection Technique

Inverse beta decay:

  e  p  e

  n

p νe e+ n Gd/H γ γ γ γ γ

<Eν> ~ 4 MeV

Gd doped liquid scintillator:
Prompt e+ annihilation: Evis ≃ E – 0.8 MeV
Delayed γs from n capture by:

Gd:Δt ~ 30μs, E ~ 8 MeV σ = 49000b H: Δt ~ 200μs, E ~ 2.2 MeV σ = 0.3b

Liquid scintillator: capture escaping γs
Non-scintillating buffer region contains PMTs

Eth = 1.8 MeV

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Mark Dierckxsens TAUP 2009, July 2009 5-1

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Backgrounds

Accidental background

e like signal radioactivity from PMTs, materials, rock neutron like signal n generated by cosmic μ, γ mimicking n signal

Correlated background

Fast neutrons: produced by cosmic μ recoil p + Gd capture Long lived isotopes 9Li (8He, 11Li): β-n decay τ ~ 100ms AND OR

+

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Mark Dierckxsens TAUP 2009, July 1-5 2009

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Double Chooz Experiment

Near 8.6t

verbdn 45m

400m Far 8.6t

verbdn 110m

1050m

Chooz-B Power Plant

2 cores, 8.6 GWth

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Mark Dierckxsens TAUP 2009, July 1-5 2009

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Status of Double Chooz

Far detector under construction
Buffer PMTs installed last

month, acrylic vessels integration started

Phase I: data taking with far

detector only from spring 2010

Near lab will be available

at end of 2010

Phase II: data taking with

both detectors in 2011

See talk J. Maricic

Far hall Far PMTs

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Mark Dierckxsens TAUP 2009, July 1-5 2009

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RENO Experiment

YeongGwang Power Plant

6 cores, 17.3 GWth

290m Near 20t 70m overbdn Far 20t 200m overbdn 1380m

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Mark Dierckxsens TAUP 2009, July 1-5 2009

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Status of RENO

Provided by Soo-Bong Kim

Near & far tunnels completed
Oct 2009: Steel/acrylic vessels &

support installation

Early 2010: both detectors ready for

data taking

Test mock-up detector (1/10) ongoing

Detector pit Tunnel entrance Mock-up detector

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Mark Dierckxsens TAUP 2009, July 1-5 2009

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Daya Bay Experiment

Daya Bay Ling Ao Ling Ao II (2011)

HONG KONG

Daya Bay/Ling Ao Power Plant

4 cores, 11.6 Gwth
2011: 6 cores, 17.4 GWth

DYB Near 2x20t

verburden: 95m

Far 4x20t

verbdn 355m

DYB Near 2x20t

verbdn: 95m

LA Near 2x20t

verbdn 112m

1985m 1615m

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Mark Dierckxsens TAUP 2009, July 1-5 2009

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Status of Daya Bay

March 2009: surface assembly building
ccupancy
Summer 2009: DB near hall occupancy
Fall 2009: first detector ready
Summer 2010: DB near hall ready for data
Summer 2011: far hall ready for data

See talk K. Heeger

Assembly building Tunnel Acrylic vessel

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Mark Dierckxsens TAUP 2009, July 1-5 2009

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Expected Sensitivities

Expt σstat [%] σsyst rel. [%] sin22θ13 > (90% CL) Double Chooz 0.5 0.6 0.03 RENO 0.3 0.5 0.02 Daya Bay 0.2 0.4 0.01

Far only Near & Far Double Chooz

Exposure time (years) sin22θ13 90% CL

Daya Bay

sin22θ13 90% CL

RENO

sin22θ13 Δm2

31 (x10-3)

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Mark Dierckxsens TAUP 2009, July 1-5 2009

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LSND Experiment

 E = 20-55 MeV, L = 30m
look for e in liquid scintillator

detector

excess over background:

87.9 ± 22.4 ± 6.0

3.8σ evidence for oscillations
L/E requires Δm2 very

different from solar and atmospheric Δm2

3 mass differences requires

mixing with a 4th type of neutrino with different mass: evidence for sterile neutrinos?

Aguilar et al. PRD64:112007,2001

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Mark Dierckxsens TAUP 2009, July 1-5 2009

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MiniBooNE Experiment

Booster

K+

target and horn detector dirt decay region absorber

primary beam tertiary beam secondary beam

(protons) (mesons) (neutrinos)

+

  e

neutrino-mode flux

 ~ 6% e ~ 0.5%

8.9GeV GEANT4 sim

Same L/E as LSND but different

experimental environment

<E> = 700MeV, L = 500m
800t mineral oil Čerenkov detector
protons-on-target collected:
6.5 1020 PoT in neutrino mode
5.1 1020 PoT in anti-neutrino mode;

approved for 5 1020 PoT more

See talk M. Shaevitz

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Mark Dierckxsens TAUP 2009, July 1-5 2009

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  e

No excess of events in LSND

signal region (>475 MeV)

Ruled out 2  oscillations as

source of LSND signal (if no CP & CPT violation)

Full data sample analyzed

(6.5 1020 PoT)

Select charged current

quasi-elastic e interactions

A.A. Aguilar-Arevalo et al. PRL 98, 231801 (2007); PRL 102, 101802 (2009)

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Mark Dierckxsens TAUP 2009, July 1-5 2009

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  e at Low Energies

Shape not consistent with

2 oscillations

Magnitude consistent with LSND
Observed with NuMI neutrinos.

Results with more data and improved errors underway.

Excess of events at low energy: 128.8 ± 20.4 ± 38.3 (3.0σ)
P. Adamson et al.,

PRL 102, 211801 (2009)

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Mark Dierckxsens TAUP 2009, July 1-5 2009

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  e

Direct test of LSND
First result with 3.4E20 PoT

A.A. Aguilar-Arevalo et al., arXiv:0904.1958 [hep-ex]

No excess above expectations:
200-475 MeV: -0.5 ± 11.7 events
475-1250 MeV: 3.2 ± 10.0 events
3x data sample expected

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Mark Dierckxsens TAUP 2009, July 1-5 2009

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μ and μ disappearance

Set limits in unexplored

parameter space for μ and μ disappearance

Update incorporating SciBooNE

data underway (SciBooNE is a fine-grained tracking detector ~100m from the target which took data from June 2007 until August 2008)

A.A. Aguilar-Arevalo et al., arXiv:0903.2465 [hep-ex]

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Mark Dierckxsens TAUP 2009, July 1-5 2009

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MicroBooNE

LArTPC detector: advance LAr R&D and

investigate MiniBooNE low-energy excess (electrons or photons) & cross sections

70-ton fiducial volume, near MiniBooNE.
Received Stage-1 approval at Fermilab

and initial funding from DOE and NSF.

May begin data taking as early as 2011.
ArgoNeut: 170L LAr, currently taking data

in NuMI beam See talk J. Spitz

 DIS candidate  

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Mark Dierckxsens TAUP 2009, July 1-5 2009

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OscSNS

SNS at ORNL: 1 GeV, 1.4MW,

pulsed (60Hz) pulsed proton beam

MiniBooNE-like detector with

scintillator at ~60m

e and e appearance,

 disappearance, sterile neutrinos

LSND best fit

π+ decay at rest

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Mark Dierckxsens TAUP 2009, July 1-5 2009

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Cross Section Measurements

MiniBooNE SciBooNE MINOS, MINERvA T2K NOvA

Intense neutrino sources allow for much improved cross section

measurements

Important for future neutrino
scillation experiments
perating in few GeV range
Ongoing/planned experiments:
MiniBooNE and SciBooNE
MINOS and MINERvA
T2K and NOvA
Many updated and new

results shown at NuInt09:

CCQE, CCπ+, CC & NC π0,

CC coherent π+ & π0, NC elastic scattering

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Mark Dierckxsens TAUP 2009, July 1-5 2009

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CCQE Cross Section

preliminary

MINOS, MINERvA

preliminary MA = 1.35 ± 0.17 GeV Carbon target MA = 1.35 ± 0.16 GeV Iron target

MA: axial form factor in

Relativistic Fermi Gas model

MiniBooNE & MINOS (and

KEK) prefer higher value than

lder measurements on D2

and on Carbon (NOMAD)

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Mark Dierckxsens TAUP 2009, July 1-5 2009

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Summary

Reactor neutrino experiments:
Construction of 3 reactor experiments progressing well

Thanks to everyone who knowingly or unknowingly has contributed to this talk!

MiniBooNE:
  e: LSND excluded, low energy excess
  e: low statistics, now excess
 &  disappearance: exploring new parameter space
Many new cross section measurements from MiniBooNE,

SciBooNE and MINOS. Important for future long baseline experiments. expected start sin22θ13 > Double Chooz 2010/2011 0.06/0.03 RENO 2010 0.02 Daya Bay 2011 0.01