# Presentation: 470703

## MiniBooNE Neutrinos at MINOSSimona Murgia H. J. Kang, T. Yang, S. Wojcicki Stanford UniversityD. Bogert, P. Shanahan, W. SmartFermilab

- MINOS Collaboration Meeting
- Jun 4-10, 2006

## Geometry

- NuMI Target

- MINOS ND

- 

- 

- : off-axis angle to the MINOS detector = **9.13** deg
- : incident angle of MiniBooNE neutrinos on MINOS ND = **16.9** deg

- Projected view

- MiniBooNE Det

- Incoming direction of MB neutrinos:zenith: 83.5 deg
- azimuth: 172.8 deg

## Kinematics

- E:  energy in Lab frame                             :  angle in Lab frame
- M: pion or kaon mass, m: muon mass,  :  angle in the CM frame

-  Two-body decay in Lab frame:

** ****For ******** = 159****±****1.2 ****mrad (9.13 deg), get highly monochromatic ******** beam**

** ****Max E******** : 1.5 GeV for K, 189 MeV for ******
******from ******** decays hard to separate from noise**

## What can we do with MB ’s?

**Highly monoenergetic ******** beam:**
- Determine the energy scale
- K/ production rates
- Better signal/background discrimination for e
- Study cross sections for different interaction channels
- Anomalous e    production
**For now,  ************ CC only**
**Latest results:**
- Fit energy spectrum to shower energy scale and offset
- Fit energy spectrum to K/content
- Have three simulation:
**gmini: our own simulation of the MiniBooNE beamline**
- PBEAM
- MB MC: provided by MB collaboration (many thanks to S. Brice)

## Selection - Cuts

- Search for MB neutrinos in MINOS ND cosmics data stream:
-      between NuMI spills, data is recorded if at least 10 planes have a hit above ~1/3 pe.
-     (4 out of 5 consecutive planes as of Dec 05)
- Mar 05 to Feb 06 MINOS ND data has been processed (R1.18.2). For now only consider data at nominal horn current (Mar-Nov 05).
**R1.18.2 spill reconstruction** (MB s coming from the South). Process only +-1ms from MB spill.
- Select events with:
**At least a track with contained vertex** (within 1 m radius around beam direction
- and 0.5 m to 6 m into detector)
**Contained track end** (remove stopping muons reco’d with wrong direction)
-                   trk.end.x [-0.5,2.9]      trk.end.u [-0.6,2.3]
-                   trk.end.y [-1.5,1.4]      trk.end.v [-2.5,0.6]
**Track direction to loosely point back to MB target**: cos()>0.6, **** = angle between track and MB target to MINOS ND direction
**Timing of hits along track consistent with correct direction**:
**Remove large energy deposit**: momentum < 4 GeV & shower E < 4 GeV; 1 event

**Thanks to Steve Brice for providing the MiniBooNE spill timestamps (ACNET)**

******t****rms**** <1.5ns**

## Selection - Cuts

**|dt| **= Difference between MB spill and MINOS ND timestamp**<10 ********s**
-      dt corrected for difference in nsec counting between MB and MINOS

**Red: Fid. containment****Green: cos(********)>0.6****Blue: Timing cut (********t****rms**** <1.5ns)****Pink: end of track containement****Black: 1 event, track momentum < 4 GeV **
**shower E < 4 GeV**
**Dashed: Antineutrinos (reverse horn current running)**

- =1.987s

**Estimated background in +/-10********s time window : 2.9**

## PID Selection

- Select MB events with PID parameter based on track cos() and trms:
**Cut on PID>-0.2. 136 events survive**
-      (135 with cut selection).
- We loose 1 events at 8 s and gain 2 events at 2 s.
**No significant improvement**.

- PID

**MB MC**
**COSMICS**

**PID>-0.2**
**PID<-0.2**

- Data

## POT

**Nominal horn current: 1.895e20 POT**

## MC Simulation 

** ************ ****flux from MB target at ND:**

-                **MB MC**

**PBEAM**

-  PBEAM predicts smaller /K ratio at higher energies, ~ 30% more events.
-  Disagreement motivated us to have our own MC simulation of the MB beamline.

## gmini

- Proton beam direction

- Neutrino energy spectrum

- It includes most of the MB beam components : target, horn, horn shield, collimator, decay pipe and 50 m absorber.

-  **Implementation of MiniBooNE beam line in GNUMI**
-  In great shape – Need to generate more statistics (so far ~5x data)

## MB MC – Data Comparison

- Rescale to same POT as the data. Observe ~25% suppression in rates in MB MC
- No background subtraction in data. Under study.

**Data**
**MB MC intranuke on**
**MB MC intranuke off**

## MB MC – Data Comparison

**Data**
**MB MC intranuke on**
**MB MC intranuke off**

## MB MC – Data Comparison

**Data**
**MB MC intranuke on**
**MB MC intranuke off**

## Fit Energy Spectrum to /K content

**Data**
**MC**
**MC pion**
**MC kaon**
**Best fit MC**

- Best fit : kaon fraction : 42%, pion fraction : -100%
- ndf = 26.5/15

- 2

** ****Vary ********/K contribution to the neutrino spectrum:**
****** ****from pions : [-100%, 50%],  ******** from kaons :  [0%, 100%]**
** ****E************>0.75 GeV**

- ★

****

**K**

## Fit Energy Spectrum to Eshw Scale/Offset

- Fit reconstructed neutrino energy spectrum for shower energy scale and offset in a **50x50** grid:
- shower energy scale: -50% to +50%
- shower energy offset: -500 MeV to +500 MeV
- Use MB MC (will repeat with gmini when we have more statistics).
**Rescale MC to same number of events as in the data****.**
- Fit all energies and E>0.8 GeV

**DATA**
**MC: Nominal E****shw**
**MC: 1.5(E****shw****)+500MeV**
**MC: 0.5(E****shw****)-500MeV**

**E********>0.8 GeV**

**E******

**E******

## Fit Result - 2 Test

- Fit Result - 2 Test

**All E********: **
- Best fit** **2 /ndf = 1.58
- Offset: **240 MeV** Scale: **-42%**
**E********>0.8 GeV: **
- Best fit** **2 /ndf = 1.17
- Offset: **80 MeV** Scale: **-36%**

- 2

**E********>0.8 GeV**

- ★

- ★

- Offset

- Scale

** ****Better agreement for E********>0.8 **
**    **

## Fit Result - 2 + Penalty

**E********>0.8 GeV**

- ★

- ★

- Fit Result - 2 + Penalty

**Shower energy scale: 10%**
**                          ****offset: 150 MeV**
**All E********: **
- Best fit** **2 /ndf = 2.68
- Offset: **40 MeV** Scale: **0%**
**E********>0.8 GeV: **
- Best fit** **2 /ndf = 2.29
- Offset: **-20 MeV** Scale: **2%**

- 2

- Offset

- Scale

** ****Fit prefers smaller changes in shower energy**
** ****No change consistent at 1******

## Fit Result - 2 + Penalty

- Fit Result - 2 + Penalty

** ****Energy uncertainty: 6.3%**
**                          **
**All E********: **
- Best fit** **2 /ndf = 2.67
- Offset: **40 MeV** Scale: **-12%**
**E********>0.8 GeV: **
- Best fit** **2 /ndf = 2.08
- Offset: **40 MeV** Scale: **-12%**

- 2

**E********>0.8 GeV**

- ★

- ★

- Offset

- Scale

** ****Fit prefers smaller changes in shower**
**    ****energy. No change consistent at 1******
** ****Correlation **

## Best Fit Spectra

**DATA**
**MC: Best Fit w/o Penalty**
**MC: Best Fit  w/ Penalty **

**Ignoring normalization and fixing the muon energy scale, data/MC fit favors small or no change (at 1 ********) in shower energy scale and offset (if penalty is included). **

**E********>0.8 GeV**

## MB MC - Energy Resolution

- Red: shwgev
- Blue: shwlinCCcor
- Black:
- Green:

**INTRANUKE OFF**

**INTRANUKE ON**

## Conclusions/Ongoing work

- We have developed an alternative, PID-based selection of MB events. No significant improvement from original, cut-based selection is observed.
**We have performed first fits of the energy spectrum to shower energy scale, offset as well as to K/********content.**
- Need better understanding of normalization before costraining  K/content (25% discrepancy in event rates between MC and data)
**We have implemented the MB beamline in GNUMI, gmini.**
- Plans:
- Generate more statistics with gmini
- Repeat fit procedure with gmini.
- Combine normalization and energy fit.
- Study NC background.