# Presentation: 834620

## Very Long Baseline Neutrino Beams – m232 Nodes

**Fermi momentum**
**Dominated regime**

**n = 1**

**n = 5**

**n = 4**

**n = 3**

**n = 2**

**BNL – Homestake**
**3 - 4 nodes visible**

**FNAL – Soudan**
**1 node visible**

**Very Long Baseline Neutrino Beams – ********m****23****2**** Nodes**

** ****neutrino node pattern is**
**   ****key to high-resolution**
**   ********m****2**** measurements**
** ****Fermi momentum sets**
**   ****E********>1 GeV/c to maintain**
**   ******** ****energy resolution**
** ****the distance scale is set**
**   ****by ********m****23****2**** **
** ****BNL happens to be in**
**   ****a perfect location for**
**   ****the next-generation**
**  ********oscillation experiment**** **

- T. Kirk – September 11, 2002

- Ref. M. Diwan, August 2002

- Figure 1

## Neutrino Experiments Resolution Capability

**Neutrino Experiments Resolution Capability**

**Minos**
**3 years**

**BNL – Homestake**
** ****5 years**

**Super-K**
**2002**

**90% confidence**
**contours**

** ****the present Super-K will be**
**   ****improved by factor of 2**
** ****the Minos experiment is**
**   ****limited by the short**
**   ****baseline and the detector**
** ****the BNL – Homestake**
**   ****experiment exploits the**
**   ****very long baseline to the**
**   ****Homestake Mine and a**
**   ****very intense ******** beam**
** ****the water Cerenkov method**
**   ****is well matched to the exp.**

- Ref. M. Diwan, August 2002

- T. Kirk – September 11, 2002

**Allowed with 90%**
**Confidence**

- Figure 2

## Potential BNL Homestake  Neutrino Beam

- T. Kirk
- September 11, 2002

**Potential BNL ********Homestake  Neutrino Beam**

**2540 km**

**Homestake**

**BNL**

- Figure 3

## BNL-Homestake –  Disappearance Signal

**BNL-Homestake – ************ Disappearance Signal**

**No Oscillations**
**13290 events**

**Signal + Bckg.**
**6735 events**

**Bckg. Only**
**1255 events**

**Neutrino Beam – double horn**
**Distance – 2540 km**
**Target – 1 MW @ 2.5 Hz**
**Detector – 0.5 MTon H****2****O**
**Time – 5 years @ 10****7**** sec/yr**
******m****12****2**** = .00005; ********m****23****2**** = .003**
**             ****Sin****2****(2**************

** ****the neutrino node pattern**
**   ****provides high ********m****23****2**
**   ****resolution and inherent**
**   ****flux normalization**
** ****the background oscillates**
**   ****as well as signal but**
**   ****shifted down in energy**
** ****the background signal is**
**   ****measured *****independently***
** ****the geographical aspects**
**   ****are critical to this method**
**   ****(very long earth baseline)**** **

- Ref. M. Diwan, August 2002

- T. Kirk – September 11, 2002

- Figure 5

## BNL-Homestake –  Disappearance Signal (Cont.)

**   ****provides high ********m****23****2**
**   ****resolution and inherent**
**   ****flux normalization**
** ****the background oscillates**
**   ****as well as signal but**
**   ****shifted down in energy**
** ****the background signal is**
**   ****measured *****independently***
** ****the geographical aspects**
**   ****are critical to this method**
**   ****(very long earth baseline)**** **

**BNL-Homestake – ************ Disappearance Signal (Cont.)**

**Neutrino Beam – double horn**
**Distance – 2540 km**
**Target – 1 MW @ 2.5 Hz**
**Detector – 0.5 MTon H****2****O**
**Time – 5 years @ 10****7**** sec/yr**
******m****12****2**** = .00005; ********m****23****2**** = .001**
**             ****Sin****2****(2**************

**No Oscillations**
**13290 events**

**Signal + Bckg.**
**4927 events**

**Bckg. Only**
**910 events**

- Ref. M. Diwan, August 2002

- T. Kirk – September 11, 2002

- Figure 6

## BNL-Homestake – e Appearance Signal

**Neutrino Beam – double horn**
**Distance – 2540 km**
**Target – 1 MW @ 2.5 Hz**
**Detector – 0.5 MTon H****2****O**
**Time – 5 years @ 10****7**** sec/yr**

**Signal + Bckg.**
**346 events**

******e**** Bckg.**
**70 events**

**Total Bckg.**
**146 events**

******m****12****2**** = .00006**
******m****23****2**** = .002**
**Sin****2****(2**************

** ****the neutrino node pattern**
**   ****provides high ********m****23****2**
**   ****resolution and inherent**
**   ****flux normalization**
** ****the statistics for normal**
**   ****ranges of the parameters**
**   ****are adequate for measuring**
**   ********m****12****2 ****with good accuracy**
** ****the background can be**
**   ****measured in a small, near**
**   ****detector if desired (or from**
**   ****other neutrino exps.)**
** ****the geographical aspects**
**   ****are critical to this method**
**   ****(very long earth baseline)**** **

- Ref. M. Diwan, August 2002

- T. Kirk – September 11, 2002

## BNL-Homestake – e Measurement Sensitivity

** ****for experimentally favored**
**   ****parameter ranges for ********m****23****2**
**   ****BNL has the best sensitivity**
**   ****to measure Sin****2****(2********13****)**
** ****continuing improvements **
**   ****in the BNL beam design**
**   ****expected to improve the**
**   ****Sin****2****(2********13****)**** ****sensitivity in**
**   ****the higher ********m****2**** range**
** ****the geographical aspects**
**   ****are critical to this method**
**   ****(very long earth baseline)**** **

**Measureable!**

**Favored ********m****23****2**** mass range**** **

- Ref. M. Diwan, August 2002

- T. Kirk – September 11, 2002

## BNL-Homestake –Measurement Summary

- Ref. M. Diwan, August 2002

- T. Kirk – September 13, 2002

******m****23****2****	**** Sin****2****(2********23****)****	****      ********m****12****2****	****  Sin****2****(2********13****)****	****    ********deg******

**0.0035 ******** ********m****23****2**** ******** 0.002**
**Sin****2****(2********13****) ******** 0.005**

**±********	****   ****±**** 1%****	****   ****± ****15%****	****   ****± ****10%****	****    ****± ****20****o**

**0.001 ******** Sin****2****(2********13****)**
** **

**±********	****   ****±**** 1%****	****   ****± ****15%****	****      ****no ****	****      ****no**
**	****	****	****   ****meas.****	****   meas.**

- matrix entries are 1 sigma errors
- for a five-year run @ 107 secs/yr

**0.0015 ******** ********m****23****2**** ******** 0.0004**
**Sin****2****(2********13****) ******** 0.0025**

**±********	****   ****±**** 1%****	****   ****± ****15%****	****   ****± ****5%****	****   ****± ****10****o**