# Presentation: 181191

## Fermilab E-898

- Ray Stefanski
- Fermilab
- Annual Users Meeting
- June 8, 2005

##                                                 _
s  How many? New flavors? / / R relationship
 Implications of LSND
 Fermilab E-898
 Accomplishments
 Progress
Concluding Remarks

- s  How many? New flavors? / / R relationship
-  Implications of LSND
-  Fermilab E-898
-  Accomplishments
-  Progress
- Concluding Remarks

**Outline**

- This talk is the complement of most
- standard neutrino talks. The picture
- of three neutrino flavors will change
- in light of LSND, and we will explore
- the implications.

**LSND**

- H. Ray

- 5/23/05

## 10-5 + 10-3 1

- LSND
- m2 ~ 1eV2
-  ~ 2°

- Atmospheric oscillations
- m2 ~ 10-3eV2
-  ~ 45°

- Solar oscillations
- m2 ~ 10-5 eV2
-  ~ 32°

- Problem: That's too many m2 regions!
- Should find: m212 + m223 = m213

- 10-5 + 10-3 1

-  the mixing angle

- H. Ray

- 5/23/05

## Atmospheric oscillations

**eigenvalue equation in three dimensions. A general solution can be written as **
**three consecutive rotations in a 3-dimensional space:**

- m2 ~ 10-3eV2
-  ~ 45°

- Solar oscillations
- m2 ~ 10-5 eV2
-  ~ 32°

**Reactor Experiments**
**Long Baseline Exps.**

**CP violating phase**

- H. Ray

- 5/23/05

## In order to provide a theoretical basis for the LSND effect, one explores the possibility of the existence of additional, non-interacting neutrinos. Models consisting a standard 3 neutrino family along with one or 2 “sterile” neutrinos, and especially the 3+2 hypothesis provides an interesting possibility. As an exercise, let’s consider a 3+3 model. 

**Whereas in 3-dimensions we work with an SO(3) symmetry, in **
**Six dimensions we need SO(6); and six dimensional matrices.**

**Our ansatz assumes a weak coupling between SM and Sterile particles. **
**Sterile and Standard Model neutrinos behave almost independently.  **
**We might ask whether U****S ****and U****SM ****share similarities? If there are two dominent**
**Mixing angles in U****S****, could there be two also in U****SM****? If LSND is a manifestation**
**Of the real world, is it unique, or might we find oscillations in other allowed**
**Regions of ********m****2**** vs. sin****2**** 2******** space?**

**GUT models and models with **
**extra dimensions favor sterile **
**neutrinos.**

- H. Ray

- 5/23/05

## CP violating effects may also be involved in the LSND signal, in which case the effect might not be seen in MiniBooNE. Some form of CP or CPT violation is the neutrino sector would provide a mechanism for leptogenesis. Because the evolution of matter over anti-matter cannot be easily explained in the quark sector, it’s important to look for answers among the leptons.

**CP violating effects may also be involved in the LSND signal, in which case the effect might not be seen in MiniBooNE. Some form of CP or CPT violation is the neutrino sector would provide a mechanism for leptogenesis. Because the evolution of matter over anti-matter cannot be easily explained in the quark sector, it’s important to look for answers among the leptons.**

**MiniBooNE can have a small**
**Signal in neutrino-mode (which could**
**Fluctuate to a null signal!) and have a**
**3X larger signal in antineutrino mode.**
**E-944 is approved to run through 2006,**
**Perhaps with antineutrinos.**

**Michel Sorel**
**Columbia**

- H. Ray

- 5/23/05

## Cosmic Microwave Background/Large Scale Structure

**Cosmic Microwave Background/Large Scale Structure**

**Big-Bang Nucleosynthesis**

- H. Ray

- 5/23/05

## Sterile neutrinos can travel off the brane just like gravitons.

**Sterile neutrinos can travel off the brane just like gravitons.**

- H. Ray

- 5/23/05

## We believe that all support should be given to MiniBooNE experiment until it provides a complete resolution of the LSND result. 

**• ****Are neutrinos Direct or Majorana?**
**• ****What is the absolute mass scale of neutrinos?**
**• ****How small is θ13?**
**• ****How “maximal” is θ23?**
**• ****Is there CP Violation in the neutrino sector?**
**• ****Is the mass hierarchy inverted or normal?**
**• ****Is the LSND evidence for oscillation true? Are there sterile neutrino(s)?**

_**(i) search for ββ0ν decay, **_
_**(ii) determination of the sign of the m^2_(13), and **_
_**(iii) measurement of the value of θ13.**_

**We believe that all support should be given to MiniBooNE experiment until it provides a complete resolution of the LSND result.**

**Theory of Neutrinos R.N. Mohapatra**
**http://www.physics.umd.edu/ep/mohapatra/apsreportshort.pdf**

- H. Ray

- 5/23/05

## 8 GeV proton beam 
 1.6 s pulse, 5 Hz rate from Booster
 p + Be  mesons
 Mesons focused by magnetic horn
 focusing increases  flux by factor of 6
allow , anti- running
 Mesons  Decay in flight s 
E ~ 700 MeV, L ~ 541 m (L/E ~ 0.77 m/MeV)

-  1.6 s pulse, 5 Hz rate from Booster
-  p + Be  mesons
-  Mesons focused by magnetic horn
-  focusing increases  flux by factor of 6
- allow , anti- running
-  Mesons  Decay in flight s
- E ~ 700 MeV, L ~ 541 m (L/E ~ 0.77 m/MeV)

**E898: MiniBooNE**

- H. Ray

- 5/23/05

## A history of amazing progress by the Booster and Accelerator Division!

**A history of amazing progress by the Booster and Accelerator Division!**

- slow start

- big finish!

- we’re still alive!

- 56% of our goal!

- Record horn performance!

- Worlds largest sample
- In this energy range!

- H. Ray

- 5/23/05

##   flux
 +-> + 
Intrinsic e flux 
From +, K+, K0L
~0.4% of  flux
comparable to osc signal!
E910  (Jon Link; paper in prep.)
, K production @ 6, 12, 18 GeV 
	w/thin Be target
HARP (CERN; LANL, Columbia)
, K production @ 8 GeV w/ 5, 50, 100%  thick Be target

-  +-> + 
- Intrinsic e flux
- From +, K+, K0L
- ~0.4% of  flux
- comparable to osc signal!
- E910  (Jon Link; paper in prep.)
- , K production @ 6, 12, 18 GeV
- 	w/thin Be target
- HARP (CERN; LANL, Columbia)
- , K production @ 8 GeV w/ 5, 50, 100%  thick Be target

-  e   Flux Determination

- 
- 

- Lee
- ee 
- Michel electrons

- H. Ray

- 5/23/05

## LMC spectrometer

- K decays produce wider
- 	angle    than  decays
-  scintillating fiber tracker

-  e   Flux Determination

**Tungsten**
**Scintillator**

**Scintillating **
**Fiber **
**Tracker**

**Permanent **
**Magnet**

- LMC 
- candidate event

- H. Ray

- 5/23/05

## Beam

- Times of hit-clusters (sub-events)
- Beam spill (1.6s) is clearly evident
- simple cuts eliminate cosmic backgrounds
- Neutrino Candidate Cuts
- <6 veto PMT hits
- Gets rid of muons
- >200 tank PMT hits
- Gets rid of Michels
- Only neutrinos are left!

- Only

- H. Ray

- 5/23/05

## Calibration System:

- Electron data
- samples
- Michel electrons
- 0 photons

- PMTs calibrated with laser system

- Cosmic Muons
- 	Stopping, through-going
- 	Very important: most neutrino events have muons

- Calibration data
- samples span
- oscillation signal
- energy range

- H. Ray

- 5/23/05

## Laser Flasks (4)
Measure tube Q, timing response
Change I = study PMT, oil 
Muon tracker
Track dir + entry point = test track reconstruction in tank
Cube System (7) 
Optically isolated scint. cubes
+ tracker = identify cosmic , michel ele of known position 
	for E calibration

- Laser Flasks (4)
- Measure tube Q, timing response
- Change I = study PMT, oil
- Muon tracker
- Track dir + entry point = test track reconstruction in tank
- Cube System (7)
- Optically isolated scint. cubes
- + tracker = identify cosmic , michel ele of known position
- 	for E calibration

- Electron samples

**Calibration**

- cosmic 

-   tracker

- scintillation cube

- Michel electron

- H. Ray

- 5/23/05

## Sources of s  to test and measure 

**Sources of ************s  to test and measure **
**the detector’s response.**

**Michel Electrons : **
**	****fix detector E scale, **
**	****14.8% E reconstruction **
**	****@ 50 MeV**
******0**** : mass peak, E scale **
**and resolution at medium E**

- H. Ray

- 5/23/05

##    Analysis in

**E****e****  < 1000MeV**
**Expect ~100 events**
**Purely leptonic**
**small ******** uncertainty  **
**Event selection based on very**
**	****forward kinematics **
**Used previously to measure sin****2********W****  and  ********B**** **

-    Analysis in
- Progress!

-  Currently  in use for
- validating
- e PID!

- “Low Energy Electron Samples”

**Michel Electrons**
**E****e****  < 52MeV**
**Unlimited supply**
**(2 KHz stopping  ******** rate)**
**Also fixes energy scale **
**	****for calibration**

- H. Ray

- 5/23/05

##  e yield from Kaon decay:

-  e yield from Kaon decay:
**BR( K****+  ******** ********e****) = 5%**
**BR( K****0****  ******** ********e****) = 30%**

**High Energy Box**
**E****e****  >1.5 GeV**

- H. Ray

- 5/23/05

## “Electrons from NuMI” (The E-898 e calibration beam)

**“****Electrons from NuMI” (The E-898 ********e**** calibration beam)**

**Neutrino interactions have been observed in the E-898 detector, **
**generated by neutrinos from the NuMI beam. MiniBooNE can now claim to**
**be the world’s first off-axis detector.**

-  **E-898 is 111 mrad off the NuMI beam axis, and **
**	****750 m away from the NuMI target.**
** ****E-898 triggers off the NuMI extraction kicker in **
**	****the Main Injector.**
** ****The beam spill contains 5 batches in 8  ********s.**
** ****A few 1000 events are expected in the range**
** ****0<E****visible****<2 GeV by the 2005 shutdown.**
** ****The measured    ratio is a few percent ******** should **
**	****provide thousands of   events for ****	****calibration and particle ID validation!**

- H. Ray

- 5/23/05

## Data processing chain
~595,000 neutrino events recorded so far...
~5.61020 POT
~222K CCQE
~141K CC +
~90K NC Elastic
~39K NC 0

**~595,000 neutrino events recorded so far...**
**~5.6********10****20**** POT**
- ~222K CCQE
- ~141K CC +
- ~90K NC Elastic
- ~39K NC 0

- (CCQE)

- (NCE)

- (CC +)

- (NC 0)

-  **********Physics**

- H. Ray

- 5/23/05

## Identify events using hit topology
Use a “boosted tree” algorithm 
	and ANN to separate e, mu, pi, delta
Particle ID Variables 
Reconstructed physical observables
Track length, particle production angle relative to beam direction
Auxiliary quantities
Timing, charge related : early/prompt/late hit fractions, charge likelihood
Geometric quantities
Distance to wall

- Use a “boosted tree” algorithm
- 	and ANN to separate e, mu, pi, delta
- Particle ID Variables
- Reconstructed physical observables
- Track length, particle production angle relative to beam direction
- Auxiliary quantities
- Timing, charge related : early/prompt/late hit fractions, charge likelihood
- Geometric quantities
- Distance to wall

**Nuc. Inst and Meth A, Vol 543/2-3**

-  **Particle Identification**

- H. Ray

- 5/23/05

## 
Largest class of evts; use to validate flux, 
 predictions
Intrinsic e bgd due to  decay can be 
constrained
Will search for  disappearance for m2 ~0.1 - 10 eV2
Event Selection
Use Fisher discriminant to isolate events with -like Cerenkov ring in final state
Preliminary comparisons between measured distributions and MC expectations
Ex: Q2 (sensitive to nuclear effects such as Pauli blocking)

- Largest class of evts; use to validate flux,
-  predictions
- Intrinsic e bgd due to  decay can be
- constrained
- Will search for  disappearance for m2 ~0.1 - 10 eV2
- Event Selection
- Use Fisher discriminant to isolate events with -like Cerenkov ring in final state
- Preliminary comparisons between measured distributions and MC expectations
- Ex: Q2 (sensitive to nuclear effects such as Pauli blocking)

** ************  ****CCQE**

- H. Ray

- 5/23/05

## Flux estimates
+ production, will be measured to 5% with HARP
Cross section
CCQE from axial mass uncertainty, threshold effects, Pauli blocking
Optical Model
reflects current uncertainty on optical model parameters

- + production, will be measured to 5% with HARP
- Cross section
- CCQE from axial mass uncertainty, threshold effects, Pauli blocking
- Optical Model
- reflects current uncertainty on optical model parameters

** ************  ****CCQE**

**Visible Energy is the muon kinetic **
**energy deposited in the tank**

- H. Ray

- 5/23/05

## Simple reconstruction with QE kinematics
Measure muon energy and angle 
Reconstruct neutrino energy an Q2

- Measure muon energy and angle
- Reconstruct neutrino energy an Q2

**CCQE**

- Preliminary

- Preliminary

- H. Ray

- 5/23/05

## Primary background to CCQE evts/analysis
All previous measurements at bubble                            chambers, 7000 total evts, all on light                            targets, few measurements at low E
Event Selection
At least 2 Michels, 
parent neutrino event in beam spill
Separate into near and far 
	Michels based on distance to 
	muon track
Close Michels from -
- capture on C
 = 20261.5 ns
Far michels from +
 = 21970.04 ns

- Primary background to CCQE evts/analysis
- All previous measurements at bubble                            chambers, 7000 total evts, all on light                            targets, few measurements at low E
- Event Selection
- At least 2 Michels,
- parent neutrino event in beam spill
- Separate into near and far
- 	Michels based on distance to
- 	muon track
- Close Michels from -
- - capture on C
-  = 20261.5 ns
- Far michels from +
-  = 21970.04 ns

-  **CC ********+**

- 2218±15 ns

- 2057±14 ns

- H. Ray

- 5/23/05

## Simple reconstruction (for now)
Assume events are QE with Delta, instead of having recoil nucleon 
Don’t use pion information in reconstruction

- Assume events are QE with Delta, instead of having recoil nucleon
- Don’t use pion information in reconstruction

- W

- W

- 

- 

- 

- 

- A

- A

- A

- 

- 

-  CC +

- A

- H. Ray

- 5/23/05

## Background to e appearance (dominant mis-ID)
 : crucial for distinguishing ->, ->s in atm.
+ angular distribution constrain mechanisms for                 NC 0 production

Event Selection
No decay electron, 2 Cerenkov rings > 40 MeV each
signal yield extracted from fit with bgd MC : fit assuming 2 rings
Examine mass spectrum, kinematics
Bin data in kin. quantities : 0 momentum, E asymmetry, angle of 0 relative to beam, extract binned yields
Compare distributions to MC expectations

-  : crucial for distinguishing ->, ->s in atm.
- + angular distribution constrain mechanisms for                 NC 0 production
- Event Selection
- No decay electron, 2 Cerenkov rings > 40 MeV each
- signal yield extracted from fit with bgd MC : fit assuming 2 rings
- Examine mass spectrum, kinematics
- Bin data in kin. quantities : 0 momentum, E asymmetry, angle of 0 relative to beam, extract binned yields
- Compare distributions to MC expectations

-  NC 0    Jen Raaf, Cincinatti

- H. Ray

- 5/23/05

## 0 momentum = good data/mc agreement.  

**Errors are shape errors **
**Dark grey :    flux errors**
**Light grey : optical model**

- 0 momentum = good data/mc agreement.
- 	Fall-off at high p = due to flux falloff
- Cos 0 sensitive to production mechanism (coherent = forward, resonant = not so forward)

-  NC 0

- H. Ray

- 5/23/05

**Notes:**

Mass distribution : background peak near mpi0 expected due to final state interactions and multi pion events

## MiniBooNE oscillation sensitivity for 1021  p.o.t. (top) and 5 X 1020 (bottom) using the energy fit method. Blue (yellow) is LSND’s 90% (99%) CL allowed region

**MiniBooNE oscillation sensitivity for 10****21****  p.o.t. (top) and 5 X 10****20**** (bottom) using the energy fit method. Blue (yellow) is LSND’s 90% (99%) CL allowed region**

- H. Ray

- 5/23/05

## The LSND effect provides a hint of what might be a complex and wonderful world of extra neutrios.
MiniBooNE has accumulated ~56% of 1021 pot needed for 4-5  coverage of LSND
Already have worlds largest  dataset in 1 GeV range
Reconstruction and analysis algorithms are working well :
 CCQE : compare with flux predictions, disappearance analysis
 CC + : measure cross section, oscillation search
 NC 0 : measure cross section, analyze coherent contribution
e appearance analysis well under way; plan on opening box in late later this year. 
E-944 is approved to run through 2006, perhaps with anti-neutrinos.

- MiniBooNE has accumulated ~**56%** of 1021 pot needed for 4-5  coverage of LSND
- Already have worlds largest  dataset in 1 GeV range
- Reconstruction and analysis algorithms are working well :
-  CCQE : compare with flux predictions, disappearance analysis
-  CC + : measure cross section, oscillation search
-  NC 0 : measure cross section, analyze coherent contribution
- e appearance analysis well under way; plan on opening box in late later this year.
- E-944 is approved to run through 2006, perhaps with anti-neutrinos.

**Conclusion**

- H. Ray

- 5/23/05

## Backup Slides

## 800 MeV proton beam -> water target
167 ton, liquid scintillator, 25% PMT coverage
E ~ 20-53 MeV, L ~ 25 - 35 m (L/E ~ 1m/MeV)
Measure   e osc. from DAR 
 P = 2.640.670.45 x 10-3, see 4 sigma excess

- 167 ton, liquid scintillator, 25% PMT coverage
- E ~ 20-53 MeV, L ~ 25 - 35 m (L/E ~ 1m/MeV)
- Measure   e osc. from DAR
-  P = 2.640.670.45 x 10-3, see 4 sigma excess

-  LSND

- H. Ray

- 5/23/05

## Muon magnetic moment search
Massive R, expect non-zero muon mag moment
Need full dataset
Rare particle searches
Take advantage of beam structure
Proton dribble monitor 
	(if p between buckets, 
	no search!)
Astrophysics
Supernova searches
Gamma Ray bursts (GRB 030329)
Solar flare emission searches
Gamma Ray bursts

- Massive R, expect non-zero muon mag moment
- Need full dataset
- Rare particle searches
- Take advantage of beam structure
- Proton dribble monitor
- 	(if p between buckets,
- 	no search!)
- Astrophysics
- Supernova searches
- Gamma Ray bursts (GRB 030329)
- Solar flare emission searches
- Gamma Ray bursts

-  Exotic Searches

- H. Ray

- 5/23/05

##  – sum over (polarity X tree weight) in all trees

**1. Boosting: how to split node ?**
** – ****choose variable and cut **

**2. Boosting: how to generate tree?**
** – ****choose node to split **

**3. Boosting: how to boost tree ?**
** – ****choose algorithm to change event weight**

**Define Gini Index = P (1 - P) and P =∑****ω****S****/ ∑****ω****(S+B)****  here, *****ω***** is event weight**
**For a given node, determine which variable and cut value maximizes:**

**G ****= GiniIndex****Father**** – ( ****GiniIndex****LeftSon****  + GiniIndex****RightSon**** )**

**Among the existing leaves, find the one which gives the biggest ****G**
**and split it. Repeat this process to generate a tree of the chosen size. **

**Take ALL the events in a leaf as signal events if there are more signal **
**events than background events in that leaf. Otherwise, take all the events **
**as background events. Mark down those events which are misidentified. **
**Reduce the weight of those correctly identified events while increase the **
**weight of those misidentified evens. Then, generate the next tree.**

**4. Boosting: output value**
** – ****sum over**** ****(****polarity **X** tree weight) in all trees**

**See**** B. Roe et al. NIM A543 (2005) 577 ****and**** references therein**

-  Particle ID Software Optimization

- H. Ray

- 5/23/05