# Presentation: 070500

## Muon Collaboration Status

- Collaboration Goals
- HEPAP sub-panel recommendation
- Physics evolution (since sub-panel presentations)
- Technical progress (since sub-panel presentations)
- International cooling experiment
- Funding history
- Appeal
- Summary

- 124 Scientists & Engineers from 33 Institutions

- Co-spokespeople:  Steve Geer  &  Bob PalmerProject Manager:   Mike Zisman

- Steve Geer                                                                                   HEPAP Meeting,    18 Nov. 2002

## Muon Collaboration

## Collaboration Goals

- “*To study and develop the theoretical tools and the software **simulation tools, and to carry out R&D on the unique hardware,**required for the design of Neutrino Factories and Muon Colliders*.”

- The collaboration is governed by a charter which defines its
- goals and organization. The goals are defined :-

- Steve Geer                                                                   HEPAP   18 November 2002

## HEPAP Subpanel Recommendation

*“**We give such **high priority** to accelerator R&D because it is **absolutely critical** to the future of our field. ... As particle physics **becomes increasingly international, it is **imperative** **that the United **States participates broadly in the global R&D program**.”*

- _Accelerator R&D_

- Steve Geer                                                                   HEPAP   18 November 2002

## Physics Evolution

- At the time of the HEPAP sub-panel presentations the scenario yielding the weakest case for a Neutrino Factory was the one in which _only_ the atmospheric  deficit was due to flavor transitions  simple 2-flavor oscillations. The recent SNO results have have removed this scenario (since solar  deficit is also  due to flavor transitions) .
- It is believed that the strongest case for a Neutrino Factory can be made for those scenarios in which the LMA solution describes the solar neutrino deficit  chance to observe CP violation in the lepton sector.  The LMA solution is currently favored.
- Preference for the LMA solution has focused attention on theoretical (GUT) modelsthat can tolerate LMA. There are now a handful of these models that make explicit predictions for the oscillation parameters, & illustrate the importance of measuring sin2213, CP, sgn[m322] ... just the parameters that a Neutrino Factory can probe.

- Steve Geer                                                                   HEPAP   18 November 2002

## Impact of correlations and degeneracies - 1

- _Impact of correlations and degeneracies - 1_

- If the LMA solution is confirmed, and the   e oscillation amplitude parameter 13 is large enough for a high-performance Superbeam to see a signal, then the dependence of  P(  e) on the  mixing parameters is complicated.

- Fits prone tocorrelationsbetween theparameters &to degenerate(false) solutions

- Steve Geer                                                                   HEPAP   18 November 2002

## Impact of correlations and degeneracies - 2

- Several groups have now made detailed studies. Conclusions are sensitive to m212  ...and will need to be revisited when we have KamLAND results.

- Steve Geer                                                                   HEPAP   18 November 2002

## GUT predictions ... an aside:

- Model 1 :  *Naturalness*   sin2213 > m2 / m3  ~  0.01

*Albright & Geer, hep-ph/0108070*

-      Model 4:  *SO(10)  with**U(1) **** Z*2***Z*2 * flavor symmetry*

- Model 2: *Phenomenological * *Model for charged**lepton mass matrix; Bi & Dai,  hep-ph/0204317  *sin2213 ~ 10-4

- sin2213  ~ (1 – 6) ** 10-3

- Model 3:  *L**e**-L****-L**** symmetry broken by Planck-**scale effects;  Babu & Mohapatra, hep-ph/0201176*
- sin2213  ~  10-3

- _GUT  predictions are all over the map_  measurements/constraints can reject models !
- If  Superbeam experiments tell us that sin2213 < 10-2-10-3  we should keep on searching !

- Steve Geer                                                                   HEPAP   18 November 2002

## Technical Progress

- The MUTAC  report (Spring 02) was very positive.  The MUTAC report received a strong letter of transmittal from our oversight group (MCOG = representatives from BNL, LBNL & FNAL Directorates):

*“  **The impressive record of progress is epitomized by the summary judgment of the report, namely, that  **The committee finds the progress since last year excellent.**  ”  *

- Since our presentations to the HEPAP sub-panel last year we have had our annual external technical review by the Muon Technical AdvisoryCommittee (MUTAC).

- Steve Geer                                                                   HEPAP   18 November 2002

## Technical Progress – Design - 1

- Reduces 6D Emitt. ~160 c.f.  15 for linear channel.
- Hardware similar to linear channel, but many hardware questions to be addressed.
- Circumference  33 m  (c.f.  108 m linear channel)   cost could be cheaper by a factor of two ?

- _Cooling Channel Progress_:        Linear transverse cooling system  Cooling Ring                                                             (cools both  Transverse & Longitudinal Emittances)

- Steve Geer                                                                   HEPAP   18 November 2002

## Technical Progress – Design - 2

- _Progress with Acceleration_:  Replace RLATwo possibly cheaper options

-                 FFAG-- Single Arcs  (vs. 4 in  RLA)-- Less RF-- 3 design concepts under study-- Workshop this & last week

-    Pulsed Synchrotron
- -- Single Arcs   (vs. 4 in RLA)
- -- Alternating Gradient Design
- -- Small Magnet
- -- 1/3 RF because more turns

- _   __Progress with Phase Rotation_:  Induction Linac replaced with RF system

- --  Performance Similar to Induction Linac
- --  Total Length 168 m  (c.f. 260 m)
- --  68 m of 200 MHz RF
-     (c.f. 260 m 1MV/m Induction Linac)
- --  Cost  Guesstimate  < 1/2

- Time

- Kinetic Energy

- Yoke:  45 x 44 cm

- Steve Geer                                                                   HEPAP   18 November 2002

## Technical Progress - Hardware

- _Technical Progress - Hardware_

- _Targetry_

- _Ionization Cooling_

-              _PROGRESS_:
- --  Absorber designed--  Thin windows tested--  5T solenoid for RF test built
- --  Two 805 MHz cavities built--  34 MV/m achieved at 805 MHz--  RF tests in magnetic field       large dark currents&breakdown

**Need target that can handle 4MW proton beam**

**Cooling channel components are demanding:**
**  ****-- Liq. H2 absorbers with thin windows**
**  ****-- 16 MV/m  200 MHz RF in multi-Tesla field**

-         _BUT WE NEED_-- Test area (back from bid)-- Absorber tests-- 200 MHz cavity (designed)-- magnet for 200 MHz test

- Steve Geer                                                                   HEPAP   18 November 2002

## Hardware Activities

- Steve Geer                                                                   HEPAP   18 November 2002

## International Cooling Experiment

- Our external technical review committee said that: *“The cooling demonstration is the **key systems test for a Neutrino Factory ”*

- Strong international collaboration has been assembled to propose a muon cooling experiment.LoI submitted to RAL early 2002 had a favorable review, & we have been invitedto (and will) submit a full proposal by the end of the year.
- RAL has assembled a project team to help.
- We have a strong international team, a good experimental design, & a laboratory interested in hosting the experiment. Now is the time to move ahead. We have submitted a proposal to NSF for support for the cooling experiment future HEPAP presentation ?

- Steve Geer                                                                   HEPAP   18 November 2002

## Funding History

- The Collaboration is supported by direct DOE & NSF funds & by support through the BNL, FNAL, & LBNL base programs. Since the HEPAP sub-panel presentations the direct DOE support has been cut by a factor of  3.4.  The total annual DOE support has been reduced from 8 M$ to 3.5 M$
- Also support from NSF at ~ 1M$/ year for 3 years (we are in year 2).

- The present level of funding is insufficient to sustain the minimum basic hardware activity needed to keep the design & simulation efforts in contact with reality.

- Steve Geer                                                                   HEPAP   18 November 2002

## Appeal to HEPAP

- The sub-panel noted in their report that it is possible there will be no onshore linear collider. In this case, as an example of a viable scenario for the U.S., the panel suggest  *”A major new neutrino facility in the US with significant international participation.”*  	**(i.e. there needs to be  Plan B, & a Neutrino Factory might be its cornerstone).**** **
- MC is a grass-roots collaboration funded directly from DOE & NSF New model for accelerator R&D involving accelerator & particle, Laboratory & University physicists.
- However, because the MC  R&D is a broad-based grass roots activity, & not based predominantly at a single Lab, no Lab director is fighting for a neutrino factory, & we do not get significant exposure in any DOE program review.
- The sub-panel recommended a funding level that, although less than we wanted, would keep Neutrino Factory & Muon Collider R&D healthy, enabling design studies & sufficient hardware activity to keep the design work in touch with reality.
- Our funding has been severely cut in FY02 and in FY03, & is now far below that envisioned by the sub-panel. The minimum hardware activity needed to inform our design & simulation work is at risk.

- Steve Geer                                                                   HEPAP   18 November 2002

## Summary

-   The MC is a grass-roots collaboration funded directly from the DOE & NSF.
-   This model for doing accelerator R&D is succeeding.
-   Since the sub-panel presentations we have:
-     (i)   Had an excellent external technical review    (ii)  Built a strong international collaboration for a cooling experiment   (iii)  Made substantial design progress that may lead to significantly reduced             Neutrino Factory cost.
-   Recent developments in neutrino oscillation physics             --  SNO results             --  Detailed studies of the impact of correlations & degeneracies             --  Explicit GUT model predictions that can accommodate LMA     add to our enthusiasm.

- Steve Geer                                                                   HEPAP   18 November 2002