SNOLAB Experimental Advisory Committee

Barry Barish SNOLAB Workshop May 12-14, 2004 A New Opportunity

To: The Scientific Community Re: A Request for Letters of Interest in Staging Experiments at SNOLAB

Dear Colleagues,

SNOLAB, an international facility for underground science, is being developed 2 km underground in INCO's Creighton mine near Sudbury Ontario, Canada. Establishing this facility provides us with new and exciting opportunities in underground science and we look forward to working with you to make SNOLAB a success.

12-May-04 SNOLAB Workshop 2 A New Opportunity

The development of this underground facility and its associated surface facilities is funded by ~$50M from various resources in Canada and in the Province of Ontario. SNOLAB will be developed near the existing SNO experiment with a joint clean area encompassing the full facility. The establishment of SNOLAB will provide opportunities to carry out the best of the next generation of international underground experiments that will benefit from the depth and from laboratory cleanliness conditions similar to those demonstrated in the existing SNO laboratory. The 6000 meter- water-equivalent depth under a flat overburden results in excellent shielding from cosmic radiation and its progenies. SNOLAB will have the lowest muon flux among operating facilities.

12-May-04 SNOLAB Workshop 3 SNO Laboratory • 2000 m rock overburden • Almost flat surface • Surface support facilities • Vertical access • Main cavity ~10,000m3

12-May-04 SNOLAB WorkshopSolar neutrino oscillation 4 ! SNOLAB Concept Rectangular Hall 60x50x50 ft Phase 2 Cryogenic Hall

Ladder Labs -- Machine shop, Low background

SNO cavity New Experiment?

12-May-04 SNOLAB Workshop 5 Why New Labs Deep Underground? • A clean, quiet and isolated setting is needed to study rare phenomena free from environmental background. Such a setting can be obtained only deep underground, where we can escape the rain of cosmic rays from outer space.

– Why do neutrinos have tiny masses and how do they transform into one another? – Are the existence and stability of ordinary matter related to neutrino properties? – Are there additional types of neutrinos? – What is the mysterious and how much of it is neutrinos? – What role do neutrinos play in the synthesis of the elements in the periodic table? – Is there a deeper simplicity underlying the forces and particles we see?

12-May-04 SNOLAB Workshop 6 Underground Laboratories

Variation of the flux of cosmic-ray muons with overburden.

12-May-04 SNOLAB Workshop 7 Scientific Motivation

• Neutrino Properties – Solar Neutrinos – Long Baseline Experiments –

• Dark Matter

• Proton Decay

• Neutrinos, Solar Energy, and the Formation of the Elements

12-May-04 SNOLAB Workshop 8 One Depth Suits All? • Cosmic rays create background events that mask the critical events being searched for. – It takes two miles of rock to absorb the most energetic of the muons created by cosmic ray protons striking the earth's atmosphere – At such great depths, the only backgrounds are made by neutrinos (which easily penetrate the whole earth but, by the same token, interact very seldom) and by local radioactivity in the rock itself – Some experiments do not require the greatest depths, while for other experiments there is no option but depth and extreme cleanliness. • The SNOLAB facility will provide new opportunities at deep depths and we seek a scientific program to take advantage of that unique feature

12-May-04 SNOLAB Workshop 9 Underground Laboratories

Variation of the flux of cosmic-ray muons with overburden.

12-May-04 SNOLAB Workshop 10 KamLAND (operated by 100m Tohoku Univ.)

Super- Kamiokande

XMASS R&D To mine ent (1.8km rance from SK) Tokyo Dark Matter exp

Plot type GW detectors • 1000 m rock overburden • The mine is no more active 20m×20m • Support facilities on the surface 100m×100m (Cryogenic) 12-May-04 SNOLAB Workshop 11 Underground Laboratories

Variation of the flux of cosmic-ray muons with overburden.

12-May-04 SNOLAB Workshop 12 INFN Gran Sasso National Laboratory

• 1400 m rock overburden • Flat cross-section • Underground area 18 000 m2 • Support facilities on the surface

12-May-04 SNOLAB Workshop 13 Gran Sasso Scientific Program Neutrinos from CERN (CNGS) Neutrinos from the Sun OPERA GNO Low energy solar neutrino Observe exp with 30ton τ-decay Ga. Em: 36tons, Pb: 2ktons

ICARUS (600ton → 3000ton) BOREXINO Real time measurement of 7Be ν. It will start µ stop and decay in e soon.

(data taken at the surface)

Neutrinos from the atmosphere LENS proposal 12-May-04 SNOLAB Workshop 14 MONOLITH not approved Gran Sasso Scientific Program

Neutrinos from Supernovae Search for non LVD Several complementary 1kton liq experiments scintillator detector Example: DAMA 100kg NaI detector

Double beta decay experiments Enriched Ge (Heidelberg-Moscow) Cryogenic techniques (Cuorecino, Nuclear reactions (two accelerators, 40 TeO2) and 400keV) Fusion reactions in the Sun Anomalous screening in metals (LUNA-2) The lab is also used for studies of 12-May-04 SNOLAB Workshopgeology and biology. 15 Underground Laboratories

Variation of the flux of cosmic-ray muons with overburden.

Proposed Multipurpose Underground Laboratory in the U.S.

12-May-04 SNOLAB Workshop 16 Proposed U.S. Underground Laboratory -- Present Context • Compelling case has been established for the broad range of science (physics, astrophysics, biology, geology and national security) at a deep underground laboratory. • The case validated by a number of studies, including – two National Research Council (NRC) reports – a soon-to-be-released National Science and Technology Council report prepared by the Interagency Working Group on the Physics of the Universe. • Proposals for Homestake mine, San Jacinto and Soudan • NSF carried out a site review process and selected Homestake as the most promising site. • Since that review, however, the pumps have been turned off at Homestake, and the mine is now flooding. • Moreover, additional sites have been put forth.

12-May-04 SNOLAB Workshop 17 Proposed U.S. Underground Laboratory -- Process at NSF • The Directorate for Mathematical and Physical Sciences (MPS) has moved to put in place a deliberate process that has NSF working with the community to develop a course of action that will realize the scientific opportunities before us. • In broad outline, NSF process consists of • returned the submitted site proposals without prejudice • informational meeting held at NSF to describe roadmap and to receive community feedback - 29 March 2004; • work with the Department of Energy (DOE) to develop mechanisms for selecting and jointly funding underground science experiments • issue a series of up to three solicitations for planning grants beginning this spring. • Underground science community is joining toward making one joint proposal to NSF for an underground laboratory

12-May-04 SNOLAB Workshop 18 Proposed U.S. Underground Laboratory -- Process at NSF • Concerning the solicitations – the purpose of the first is to provide funds to one or more groups to develop detailed science modules reflecting the range of science opportunities noted above and to specify the associated infrastructure requirements. – The second solicitation, issued at the same time, would fund several site development studies. – The final solicitation, a year or more into the future, would provide funds to develop underground laboratory proposals combining site infrastructure with a suite of initial science experiments for NSF consideration.

• The third solicitation would only occur if MPS and its partners determined that timely construction of a major new facility is needed to realize the scientific opportunities..

12-May-04 SNOLAB Workshop 19 Underground Laboratories

Variation of the flux of cosmic-ray muons with overburden.

12-May-04 SNOLAB Workshop 20 Experimental Advisory Committee

The SNOLAB Experiment Advisory Committee (EAC) is an expert and advisory panel to review Letters-of-Interest from the scientific community and, eventually, proposals for projects at SNOLAB and provide advice to the SNOLAB Director on priorities for siting experiments in the laboratory. The objectives of the EAC are: a) develop an experimental program of the highest scientific merit, b) study in detail the technical feasibility of individual projects, c) prioritize projects for siting in SNOLAB, taking into account time lines for the projects as well as scientific merit, and d) consider proposals for allocation of development space for programs that require such space for research and development.

Members of the EAC should be representative of the Canadian and international community active on underground science and have good knowledge of the scientific areas under consideration.

12-May-04 SNOLAB Workshop 21 SNOLAB EAC Membership

Barry Barish ... Chair ... Caltech

Baha Balantekin ... Univ Wisconsin, Madison Cliff Burgess ... McGill Takaaki Kajita ... ICRR Tokyo John Martin ... Toronto Ken Ragan ... McGill Kate Scholberg ... MIT Dave Wark ... Imperial College

Andrew Hime …. ex-officio (Associate Director for Scientific Development and Chair of the Scientific Executive Committee (SEC)).

12-May-04 SNOLAB Workshop 22 Letters of Intent Experiment: EXO Experiment: COBRA Contact: Giorgio Gratta Contact: Kai Zuber Scope: Double Beta Decay Scope: Double Beta Decay Workshop Presentation: Yes Workshop Presentation: Yes LOI: Expected LOI: Received ------Experiment: Majorana Experiment: SNO with Scintillator Contact: Steve Elliott Contact: Mark Chen Scope: Double Beta Decay Scope: Solar Neutrinos Workshop Presentation: Yes and Double Beta Decay LOI: Received Workshop Presentation: Yes ... with McDonald & Caccianiga Experiment: GERDA LOI: Received Contact: Iris Abt Scope: Double Beta Decay Workshop Presentation: Yes LOI: Expected

12-May-04 SNOLAB Workshop 23 Letters of Intent

Experiment: Lithium Detector ------Contact: Anatoly Kopylov Experiment: CDMS Scope: Solar Neutrinos Contact: Dan Akerib Workshop Presentation: No Scope: Dark Matter LOI: Received Workshop Presentation: Yes LOI: Note from Dan Akerib Experiment: Noble Liquid Tracking Detector Contact: Bill Willis Scope: Solar Neutrinos Experiment: ZEPLIN Workshop Presentation: Yes Contact: Nigel Smith LOI: Received Scope: Dark Matter Workshop Presentation: Yes Experiment: CLEAN LOI: Expected Contact: Dan McKinsey Scope: Solar Neutrinos and Dark Matter Workshop Presentation: Yes LOI: Expected

12-May-04 SNOLAB Workshop 24 Letters of Intent

Experiment: PICASSO Experiment: XENON Contact: Viktor Zacek Contact: Tom Shutt Scope: Dark Matter Scope: Dark Matter Workshop Presentation: Yes Workshop Presentation: Yes LOI: Expected LOI: Received

Experiment: DRIFT ------Contact: Jeff Martoff Experiment: HALO Scope: Dark Matter Contact: Charles Duba Workshop Presentation: Yes Scope: Supernova Neutrinos LOI: No Workshop Presentation: Yes LOI: No Experiment: DRIFT-III Contact: Neil Spooner Scope: Dark Matter Workshop Presentation: No LOI: Received

12-May-04 SNOLAB Workshop 25 Goals: Dirac or Majorana particle?

Majorana : The neutrino is its own antiparticle

Ettore Majorana

12-May-04 SNOLAB Workshop 26 Solar Neutrinos – The Future In the standard solar model the flux from the pp reaction is predicted to an accuracy of 1%. Further, the total flux is related directly to the measured solar optical luminosity.

Such a copious and well-understood source of neutrinos is ideal for precisely determining the neutrino masses and mixings.

It also affords a way to search for hypothesized sterile neutrinos as much as a million times lighter than those explored by present experiments, provided they mixed sufficiently with the active neutrinos.

Unfortunately, the pp neutrinos have very low energies

12-May-04 SNOLAB Workshop 27 Dark Matter – Direct Searches

12-May-04 SNOLAB Workshop 28 EAC Goal

• Work with SNOLAB and the community to develop the most promising program for the new laboratory taking into account:

– Science potential is the highest priority!

– The approved program must have significant discovery potential and strong collaborations to obtain funding

– The experiments should take advantage of the uniqueness of great depth at SNOLAB

– The program should be determined in the context of other plans worldwide.

– R&D toward proposals not yet mature should be accommodated where possible. • EAC will provide strategic and technical guidance, in order to construct a deep underground laboratory expeditiously and in synergy with a world class research program.

12-May-04 SNOLAB Workshop 29