SLIDE 1
Teresa Montaruli, Les Houches, 25 Jan. 2002 2
Neutrino measurement with MACRO: Neutrino measurement with MACRO: - - PowerPoint PPT Presentation
Neutrino measurement with MACRO: Neutrino measurement with MACRO: - - PowerPoint PPT Presentation
Neutrino measurement with MACRO: Neutrino measurement with MACRO: neutrino oscillation, dark matter and astronomy neutrino oscillation, dark matter and astronomy studies studies Teresa Montaruli Teresa Montaruli Bari University and INFN
SLIDE 2
SLIDE 3
Teresa Montaruli, Les Houches, 25 Jan. 2002 3
Outline Outline Outline
- Min rock coverage 3150 hg/cm2
- 600 ton liquid scintillator (600 ps), 20000 m2 streamer tubes (< 1º)
76.6×12×12 m3 Eth ~1 GeV @vertical
NIM A324(1993)
- Neutrino detection in MACRO since 89 to Dec. 2000 (acq end)
- Through-going upward muon results: matter effects νµ →ν
→ντ or νµ →ν →νsterile
- Low energy topologies
- Multiple scattering to infer Eν
- ν astronomy results: point-like
sources and diffuse flux
- Search for WIMPs
Clear event topologies, different energies, fully automatic analysis, no rejection of events at trigger level (efficiency, acceptance, backgrounds can be studied using atm. muons) Different technique than SuperKamiokande
SLIDE 4
Teresa Montaruli, Les Houches, 25 Jan. 2002 4
Throughgoing Internal Down Internal Up µ stop
Throughgoing: Emedian∼50 GeV 180/yr Internal Up: Emedian∼3.5 GeV 50/yr Internal Down+Stopping µ: Emedian∼4.2 GeV 35+35/yr (expected)
ν event topologies ν ν event topologies event topologies
SLIDE 5
Teresa Montaruli, Les Houches, 25 Jan. 2002 5
Main cut: position along
- scint. counter from ST
track in agreement inside 70 cm with that from ToF ~200 gr/cm2 in rock absorber to reduce at 1% background from upgoing πs No scanning, fully automatic
- 1.25 < 1/β < -0.75
Upward throughgoing µ analysis Upward throughgoing µ analysis
T.o.F. technique:
1/β distribution (full detector)
SLIDE 6
Teresa Montaruli, Les Houches, 25 Jan. 2002 6
The backgrounds The backgrounds
Incorrect β: showering events, multiple µs; large β: µ decay
MACRO Coll., Astr. Phys 9 (1998)
First study
- f physical
background to ν underground measurement Photonuclear interactions atmospheric µ ↓ produce upgoing soft particles Important for shallow detectors (Baksan, IMB while SK and Soudan2 have vetos) 243 upgoing particles between 12.2 ·106 µs ↓ ~10-4 π/µ ↓
~1% in throughgoing µs↑ ~5% in stopping µs
SLIDE 7
Teresa Montaruli, Les Houches, 25 Jan. 2002 7
Event 23 Dec 1994
Total n. of events 863 Backgrounds Incorrect β 22.5 Soft upgoing π 14.2 Internal ν interactions 17 Measured 809 Expected 1122 ± 17% (Bartol flux 14% checked on atmospheric µ data, cross sections (GRV94) 9%, µ energy Loss 5% (Lohmann et al.) R = 0.72 ± 0.026stat±0.043sys± 0.12theor
Mar 89-Nov 91 (1.4y) Dec 92-Jun 93 (0.4y) Apr 94-Dec 2000 (5.5y) 26 µ↑ µ↑ 55 µ↑ µ↑ 782 µ↑ µ↑ 1/6 lower detector Lower detector Complete detector
- Phys. Lett. B357 (1995) 481
- Phys. Lett. B434 (1998) 451
- Phys. Lett. B517(2001) 59
Results for Upward throughgoing µs Results for Upward throughgoing µs
SLIDE 8
Teresa Montaruli, Les Houches, 25 Jan. 2002 8
µ↑ µ↑ flux angular distribution µ↑ µ↑ flux angular distribution
∆m2 = 0.0025eV2
χ2 test on the angular distribution (10 bins) with prediction
normalized to data: χ2/dof=25.9/9 for no-oscillations P = 0.2% χ2/dof=9.6/9 for νµ→ντ (∆m2 = 0.0024 eV2 sin22θ=1) P = 37%
SLIDE 9
Teresa Montaruli, Les Houches, 25 Jan. 2002 9
νµ→ν →ντ oscillations in upward throughgoing µ νµ→ν →ντ oscillations in upward throughgoing µ
Peak probabilities: 37% shape 66% shape × normalization
∆m2 = 0.0024 eV2 sin22θ=1
Reduction factors for νµ→ντ MACRO threshold ~1 GeV more sensitive to vertical deficit than SK (average threshold ~6 GeV)
SLIDE 10
Teresa Montaruli, Les Houches, 25 Jan. 2002 10
Angular distribution for selected sample Angular distribution for selected sample
3 box events (redundant time measurement ⇒ low background+better time resolution) same shape of full sample χ2/dof=9.4/7 for no-oscillations P = 22.8% χ2/dof=3.7/7 for νµ→ντ (∆m2 = 0.0025 eV2 sin22θ=1) P = 81.5%
SLIDE 11
Teresa Montaruli, Les Houches, 25 Jan. 2002 11
Azimuth distribution for selected sample Azimuth distribution for selected sample
Full detector sample
Oscillations do not affect azimuth angular distribution χ2/dof=2.8/11 normalizing prediction to data
P = 0.99
SLIDE 12
Teresa Montaruli, Les Houches, 25 Jan. 2002 12
Matter effects in upward throughgoing µs
When ν flavors involved in oscillations have different weak potential in matter
sterile e n e n B F weak
Y Y Y n G V ν ν ν ν
τ µ ,
2 4 2 2 2 − + − × ± =
+ for ν, - for nB = barion density
Yn,e = n, e/barion
ν
Matter effects in upward throughgoing µs
Matter effects can be important for νµ→νe,νsterile not for νµ → ντ And for Eν/∆m2 ≥103 GeV/eV2 for HE up-throughgoing µs For maximal mixing matter effect produces a reduction of oscillation effect closer to predicted with no oscillations For mixing <1 enhancement for some values of parameters (MSW)
SLIDE 13
Teresa Montaruli, Les Houches, 25 Jan. 2002 13
Sterile or tau ν oscillations? Sterile or tau ν oscillations?
Vertical/horizontal more powerful test than χ2
- P. Lipari & M. Lusignoli, PRD57(1998)
Pbestτ =8.4%/Pbeststerile=0.033% ⇒254 νµ→νsterile excluded at ~99% c.l.
Ratio: sensitive to deviation sign, gain in statistical significance (2bins) but some feature of angular shape could be lost MACRO bin choice through simulation (MACRO Coll. Phys. Lett. B517(2001) 59)
Max mixing sin22θ=1
Peak probability for shape 1.8% Peak probability for shape×normalization = 8%
SLIDE 14
Teresa Montaruli, Les Houches, 25 Jan. 2002 14
Systematic errors in the ratio Systematic errors in the ratio
- Neutrino flux sources of uncertainty:
- P. Lipari, Nucl. Phys. Proc Supp.91(2001)
1) K/π fraction 2) Spectral index of CR E specrum
δR/R ~3%
- Comparison of different cross
sections δR/R ~2%
- Detector acceptance + background in
horizontal region
δR/R ~4.6%
Other uncertainties: seasonal variations dR/R ~1.3% + US atmosphere profile dR/R ≤1% MACRO upgoing µs: variation in vertical/horizontal ratio R(Nov-Apr) - R(May-Oct)≈0.19±0.17stat Seasonal effect difficult to calculate because neutrinos come from meson and muon decays and from all over the Earth
MACRO events θ
SLIDE 15
Teresa Montaruli, Les Houches, 25 Jan. 2002 15
Internal Up events Internal Up events
Selection Criteria: 1. ToF between central/top scintillator layers 2. Vertex containment to reject up-throughgoing µs (~1% backg) DATA 161 with -1.3< 1/β <-0.7 (eff. livetime 5.58yr) Backgrounds (wrong β, secondary hits) = 7 154 Uniform deficit
- Phys. Lett. B478 (2000) 5
∆m2=0.0025 eV2
SLIDE 16
Teresa Montaruli, Les Houches, 25 Jan. 2002 16
Internal Down + Upward Stopping Internal Down + Upward Stopping
Selection criteria: 1. no T.o.F. 2. topological cuts: fiducial volume +bottom SC layer 3. visual scanning (real+simulated events) 4. >100 gr/cm2 in lower detector (soft πs backg. ∼5%) DATA: 272 events (5.6 yr), background 10 events 262 Uniform deficit IU and ID+UGS due to CCνµ, NC and νe (~13% IU and 10% UGS+ID)
∆m2=0.0025 eV2
Predictions: Φ = Φν ⊗ σν ⊗ ε(Εµ,θ)
25% error in MC normalization 6% difference respect to MINOS Neugen
- Φν: Bartol ν flux with geomagnetic cutoff
checked on µ data (error ~ 14%)
- σν = Q.E. + 1π (Lipari et al., PRL74 (1995) 4384)
+ DIS (GRV-LO-94 PDF) (error ~ 15%)
- ε(Eµ,θzenith): detector response +acceptance
(systematic error ~ 10 %)
- Phys. Lett. B478 (2000) 5
SLIDE 17
Teresa Montaruli, Les Houches, 25 Jan. 2002 17
Low energy results Low energy results
DATA: 154 ± 12stat
MC: 285 ± 28sys ± 57theo MC (∆m2=0.0025 eV2): 168 ± 17sys ± 34theo
DATA: 262 ± 16stat MC: 376 ± 38sys ± 76theo MC (∆m2=0.0025 eV2): 284 ± 28sys ± 57theo Internal down + Upgoing stopping µ’s Internal Upward going µ’s
th sys stat IU
MC Data 11 . 05 . 04 . 54 .
) (
± ± ± =
th sys stat UGS ID
MC Data 14 . 07 . 04 . 70 .
) (
± ± ± =
+
- Zenith angular distributions
constant deficit
- RIU and RID+UGS not same
reduction deficit not due to
- theor. overestimate of ν
flux/cross sections IU and ID+UGS have <Eν> ~ 4 GeV
SLIDE 18
Teresa Montaruli, Les Houches, 25 Jan. 2002 18
Double Ratio Double Ratio
- Most of the theor. err. cancel (<5%)
- Systematic err. reduced (~6%)
Data: R = 0.59 ± 0.06stat Expected (No oscillations): R = 0.76 ± 0.04sys ± 0.04th Expected νµ ντ oscillations: R = 0.59 ± 0.04sys ± 0.03th
(max mixing and ∆m2 = 2.5 x 10-3 eV2 ) Probability to obtain double ratio so far from expected is ~2% (including non-gaussian shape of the uncertainty of the ratio) Expected reductions for ∆m2 ~1-10 ×10-3 eV2 sin22θ= θ=1 1/2 for IU 1/4 for ID+UGS (ID not reduced)
Internal Downgoing Upgoing Stop
R =
+
SLIDE 19
SLIDE 20
Teresa Montaruli, Les Houches, 25 Jan. 2002 20
Multiple Scattering: E dependence in MACRO data? Multiple Scattering: E dependence in MACRO data?
- 25 radiation lengths of absorber+iron
- ST system σ ~1cm saturation @
Eµ~10GeV
- ST resolution improved to 3mm using
TDC analogue information (150 ns) µ residual energy up to 40 GeV (Eν~200 GeV) Goal: study of atm νµ oscillations using energy estimate through multiple scattering of µ↑ Given preferred oscillation parameters ∆m2 ~O(10-3 eV2) oscillation effects stronger at Eµ≤10 GeV and disappear at E> 100 GeV NIM paper to appear
log10Eµ(GeV)
SLIDE 21
Teresa Montaruli, Les Houches, 25 Jan. 2002 21
Oscillations and Multiple Scattering Oscillations and Multiple Scattering
eV2
Preliminary
Low energy: <Eν> ~15 GeV (46 events) High energy: <Eν> ~170 GeV (55 events) Error: 11% ν flux + cross section +5% acceptance 348 of the through-going upgoing sample survived to cuts (4 ST planes with valid QTP-TDC information) NN trained to recognize residual µ energy
Next future: oscillation contour from low/high ratio
SLIDE 22
Teresa Montaruli, Les Houches, 25 Jan. 2002 22
MACRO as a ν telescope MACRO as a ν telescope
- Good pointing resolution using ST system (<1°); Moon shadow at 5.5σ level
Showers do not worsen angular res. ∆Ω(µsim−µrec)∼1° @ 100 TeV
- Timing 600 ps resolution ⇒atm µ background rejection
- Efficiency and acceptance checked at HE: monoenergetic µ beams using
Bottai&Perrone corrections to µ propagation in GEANT and rock around MACRO Area @100 TeV ~ 42% area @10 GeV due to analysis cuts (same as oscillation analysis except for 200 gr/cm2 in lower detector)
(PRD59 (1999)). MACRO Coll., AP.J., 546, 1038, 2001
MACRO area averaged over 1 day as a function of declination and energy
SLIDE 23
Teresa Montaruli, Les Houches, 25 Jan. 2002 23
MACRO response function to astrophysics fluxes MACRO response function to astrophysics fluxes
SLIDE 24
Teresa Montaruli, Les Houches, 25 Jan. 2002 24
Neutrino Astronomy with MACRO Neutrino Astronomy with MACRO
Search for clusters around µ↑ directions+sources from catalogues (SNRs, EGRET, NovaeX, Blazars, BATSE and BeppoSAX)
- Atm. ν background:
- Steady sources: 100 random associations of µ↑ local angles with times
Backg in 10º declination bands
- Pulsed sources: coincidences in ∆t = ±(20-400) s (each 20 s), 200 time
shifts of ∆t(µ↑ and GRB) (from –4000-4000 s to -80000-80000s) No statistically significant cluster
- f 1356 events around 42 selected
sources 12 sources with ≥2 events (expected 14.3) in 3º 7 events from GX339-4 (P=2.6·10-3) Prob to find such excess from ≥1 of the 42 sources Pmax = 6.5%
SLIDE 25
Teresa Montaruli, Les Houches, 25 Jan. 2002 25
Point-like source search Point-like source search
MACRO SKY SURVEY 1356 µ↑ No significant cluster around 1356 events 110 clusters with with ≥4 events around a given event 107.8 expected in 3º cone Largest cluster of 9 events around (345º,-74º)
SLIDE 26
Teresa Montaruli, Les Houches, 25 Jan. 2002 26
Neutrino Astronomy with MACRO Neutrino Astronomy with MACRO
No significant excess has been found with respect to the background 90%c.l. muon flux upper limits for 90% of signal in 3º search cones for ν flux power law with 2.1 spectral index and for Eµ ≥1 GeV Fraction
- f signal
in 3º as a function of spectral index and cos(zenith)
SLIDE 27
Teresa Montaruli, Les Houches, 25 Jan. 2002 27
ν ν emissions during GRBs ν ν emissions during GRBs
BATSE : 1 burst /day (4π/3sr)
Similar results for BeppoSAX
1230 MACRO µ↑ overlap in time with 2702 BATSE GRBs 10º (5º ) 96.9% (83.5%)
νs from GRBs (BATSE error box
dominates) ±200 s (98% GRBs T90s) 0 events (0.05 expected) MACRO area/average burst 133m2 90%c.l upper limit: 6.64 10-10 µ cm-2 per average burst 1 order of magnitude from Waxman&Bahcall fireball scenario
SLIDE 28
Teresa Montaruli, Les Houches, 25 Jan. 2002 28
Search for high multiplicity events in coincidence with GRBs Search for high multiplicity events in coincidence with GRBs
MACRO dedicated SN trigger PHRASE looks for clusters of ν-like events 1453 BATSE GRBs occurred in ∼5 yrs of SN trigger up-time
- GRB-induced variations of single event
trigger rate: ±1, ±5, ±10min intervals
RESULT: no evidence for variations Events within 10 min before and after BATSE GRBs vs SN trigger rate (= backg) Line = probability of 10-1 for
- bserving a given number of
events in a 10min interval for a detector running time
- f 5 yr
SLIDE 29
Teresa Montaruli, Les Houches, 25 Jan. 2002 29
Search for diffuse ν flux in MACRO Search for diffuse ν flux in MACRO
MACRO does not directly measure µ energy but energy released in SC boxes helps in selecting HE events after energy calibrations including non-linear terms in light yield/ADC count relation accounting for PMT saturation + tests on reliability of response @ HE using full simulation and atm µ data Released energy distribution for a sample of atm µs Calibrations @ HE for 1 box: ERP attenuated ADC response to laser light
Calibration reliable to released energy >500 MeV Linear response With higher
- rders
SLIDE 30
Teresa Montaruli, Les Houches, 25 Jan. 2002 30
ENTRIES 7547
Log10(EIni(GeV)) Log10(ERel(MeV))
1 1.5 2 2.5 3 3.5 4 4.5 5 1 2 3 4 5 6 7 8
Total energy released Initial µ energy
Analysis for diffuse ν flux search Analysis for diffuse ν flux search
AGN simulation: 2988 yrs, CTEQ3-DIS, Stecker et al. model, proper µ transport 10 TeV in GEANT, rock around detector to account for showering events
+ box with >500 MeV at d<1m
No ST tracking required Weighted mean time by energy release for scintillator plane ⇒upward direction 1/β from ‘scintillator’ track Reasonable decrease in efficiency with energy >500 MeV in 1 box
100TeV 1TeV 10TeV
>500 MeV in another box
Radiative processes
Ionization
SLIDE 31
Teresa Montaruli, Les Houches, 25 Jan. 2002 31
MACRO µ upper limit on diffuse ν flux MACRO µ upper limit on diffuse ν flux
livetime area efficiency c.l.) (90% limit Upper c.l.) (90% Φ × × =
µ
Φµ ~ 1.7 10-14 cm -2 s -1 sr -1
Prepint astro- ph/0105269
104<E<107
1.3 ÷ 1.9 10-5
BAIKAL (νe)
Nucl.Phys.Proc.S 91, 423 (2000)
E<106
1.0 10-6
AMANDA
This analysis
104 <E<106
4.5 10-6
MACRO (this analysis)
- Astrop. Phys 4, 217
(1996)
E ~2.6 103
5.0 10-6
Frejus
- Astrop. Phys 14, 61
(2000)
104<E<107
1.4 10-5
BAIKAL
Proc XXV ICRC, Durban (1997)
105<E<106
6.0 10-4
SPS- DUMAND
Phys Lett. B 333 , 555 (1994)
105<E<106
2.0 10-3
EAS – TOP
Reference ν ν Energy range (GeV) ν flux limit
(90% cl) E2Φν (GeV cm-2 s -1 sr-1)
power law index γ
γ =2
No significant signal has been found with respect to the statistical fluctuations of the atmospheric neutrino background
2
DATI
0.54±0.03stat
AGN
1.1±0.5stat
ATMO Rate of survived events in 5.8 yr
SLIDE 32
Teresa Montaruli, Les Houches, 25 Jan. 2002 32
MACRO ν upper limit on diffuse ν flux MACRO ν upper limit on diffuse ν flux
Log10(Eν(GeV)) E2Φν(GeV cm-2 s-1 sr-1)
10
- 9
10
- 8
10
- 7
10
- 6
10
- 5
2 3 4 5 6 7 8 9
Upper limit on ν ν flux (power law index γ
γ =2) Φµ ~ 1.7 10-14 cm -2 s -1 sr -1
(model dependent limit: ν spectrum, cross sections, µ energy losses)
SLIDE 33
Teresa Montaruli, Les Houches, 25 Jan. 2002 33
Candidates selected by the diffuse flux analysis Candidates selected by the diffuse flux analysis
381 tracks!
SLIDE 34
Teresa Montaruli, Les Houches, 25 Jan. 2002 34
Weakly Interacting Massive Particles in Earth and Sun Weakly Interacting Massive Particles in Earth and Sun
χ+χ→ χ+χ→ νµ+… Earth: data>background in signal region (oscillations)⇒expected background
- f atm neutrinos normalized by ratio of observed to expected events
- utside search cones
Sun: expected backg mixing randomly times and local angles of measured events⇒the method accounts for oscillations
- Phys. Rev. D60 (1999) 082002
Exposure ~ 4500m2yr
MC 1139±194
SLIDE 35
Teresa Montaruli, Les Houches, 25 Jan. 2002 35
∆m2 = 3 10-3 eV2
Models by Bottino et al
(Astrop. Phys 3 (1995)65) Circles already excluded by direct searches ρχ=0.5GeVcm-3
Effect of νµ→ντ oscillations on ν fluxes from χ annhilation
- N. Fornengo, hep-ph/0011030
ντ→νµ does not balance νµ→ντ because
Φντ<Φνµ ⇒ reduction of µ↑ χ+χ→ χ+χ→ νµ+…
Neutralinos in Earth and Sun Neutralinos in Earth and Sun
SLIDE 36
Teresa Montaruli, Les Houches, 25 Jan. 2002 36
Current results
χ+χ→ χ+χ→ νµ+… SK: exposure from Neutrino2000 1028 events/923d, limits from ICRC2000 1416/1268 d
Baksan: 1056 events, 14.8 yr (Suvorova, hep-ph/9911415)
Lake Baikal 35 vertical,/ 234 d (ICRC2000) (10 GeV) AMANDA B10: 15 vertical/135d (astro-ph/0012285)
Current results
Sorry: could not be latest results but no published ref
Different methods for upper limits! i.e. SK limits do not account for cone collection Efficiency, MACRO 90% signal included
SLIDE 37
Teresa Montaruli, Les Houches, 25 Jan. 2002 37
DAMA/NaI annual modulation indication DAMA/NaI annual modulation indication
Earth crossed by larger WIMP flux in June (December): VEarth rotation around Sun +(-) Vsolar system in Galaxy
v0=170km/s v0=270km/s
Earth fluxes
(Bottino et al. models PRD62(2000))
include νµ→ντ
DAMA/NaI (PLB480(2000)23): ~7%effect for ~4annual cycles favor MW=43 (72) GeV (local WIMP velocity v0 = 220km/s (170km/s))
CDMS (PRL84(2000)5699) excludes at 84%cl 3σ allowed DAMA region and
claims n background at a rate close to intensity of DAMA signal
SLIDE 38
Teresa Montaruli, Les Houches, 25 Jan. 2002 38
νs from WIMPs in the Galactic Center
Gondolo and Silk
(PRL83(1999)):
if CDM exists in Gal Center can be accreted by black hole with formation
- f “central spike”
If CDM = neutralinos Φν ~10-15-10-14cm-2 s-1 for mχ>50 GeV MACRO limits excludes most models with central spike
νs from WIMPs in the Galactic Center
SLIDE 39
Teresa Montaruli, Les Houches, 25 Jan. 2002 39
AMANDA, Lake Baikal
ANTARES, NEMO-RD, NESTOR