Dear P5 Committee Members:
We believe that it is critically important for the US to play a leading role in the next
generation of short-baseline oscillation experiments. In particular, we believe this effort requires
a suite of experiments that can definitively cover the allowed phase space for light sterile
neutrinos and provide a comprehensive approach to the investigation of the current neutrino
anomalies. Certain key elements of this program (e.g. accelerator-based experiments) will
require significant resources, and must have a strong endorsement from P5 to proceed. We
therefore request that P5 recommend the strongest possible program in short-baseline oscillation
physics including definitive accelerator-based experiments as well as specialized non-accelerator
experiments, and make it a top priority to definitively resolve the sterile neutrino question.
With the discovery of the Higgs, the last standard model particle, the entire field of particle
physics is now focused on an aggressive, multifaceted search for evidence of physics beyond the
standard model: new particles at the LHC; deviations from precision theoretical calculations in
muon g-2 and 𝐾 → 𝜋𝜈𝜈̅ ; flavor violating decays of the muon; direct dark matter searches; and
dark energy surveys. The search for neutrino oscillations beyond the standard 3-neutrino
paradigm is in line with this program. All of the aforementioned searches find motivation in
theory, but among these, the search for sterile neutrinos is unique in that it also finds motivation
in the data. The collection of results and anomalies that point towards the possible existence of
sterile neutrinos (LSND, the gallium anomaly, the reactor anomaly, MiniBooNE, and
cosmological fits for the effective number of neutrino families) are by no means definitive, but
neither are the existing null results.
Over the course of the last two years, our field has conducted a comprehensive review of
the evidence for and against the sterile neutrino. The work of this review was documented in
“Light Sterile Neutrinos: A White Paper” (arXiv:1204.5379 [hep-ph]), and we refer you there for
a detailed discussion. Our examination of the evidence shows, that while individually the
anomalies can be discounted or argued away, when combined, they cannot be ignored. The
major conclusion of this review was, therefore, that new definitive experiments are required.
A number of projects have been proposed, and some are underway, to continue the search
for sterile neutrinos. The sterile neutrino white paper contains an appendix with 21 different
experimental concepts, and 15 white papers for sterile neutrino measurements were received by
the Snowmass Neutrino Working Group. These proposals cover a wide range of costs and
timelines. They utilize a diverse array of neutrino sources, including reactors, radioactive
sources, accelerator beams and cosmic rays. This provides a unique opportunity for a
comprehensive, staged program with US leadership based on a suite of complementary
experiments. Source and reactor experiments will provide timely and cost-effective probes of
specific anomalies in the neutrino sector with exceptional discovery potential, while ultimately
accelerator-based experiments will be required to fully cover the allowed phase space, and
provide a definitive resolution of the sterile neutrino hypothesis. Further, should sterile neutrinos
be discovered, accelerator-based experiments are essential to fully study the sterile sector.
It is in the sterile neutrino sector that the neutrino community is engaged in the direct
search for new physics. Establishing the existence of sterile neutrinos would be a major result
for particle physics and clear evidence for physics beyond the standard model. Thus, decisive
experiments that can make this determination should be a key part of the US program. We urge
P5 to make definitive short-baseline oscillation experiments a top recommendation.
Signed,
C. Aberle, University of California, Los Angeles
C. Adams, Yale University
A. Adelmann, Paul Scherrer Institute
D. Adey, Fermi National Accelerator Laboratory
S.K. Agarwalla, Institute of Physics, Sachivalaya Marg
R. Allen, Oak Ridge National Laboratory
J. Alonso, Massachusetts Institute of Technology
C. Andreopoulos, University of Liverpool
C.M. Ankenbrandt, Muons Inc.
A. Anokhina, Lomonosov Moscow State University
J. Asaadi, Syracuse University
R. Asfandiyarov, University de Geneve
J. Ashenfelter, Yale University
J.J. Back, University of Warwick
A. Bagulya, Lebedev Physical Institute of Russian Academy of Science
B. Baller, Fermi National Accelerator Laboratory
H. Band, Yale University and University of Wisconsin
G. Barker, University of Warwick
W.A. Barletta, Massachusetts Institute of Technology
R. Barlow, University of Huddersfield
L. Bartoszek, Bartoszek Engineering
E. Baussan, IPHC, Université de Strasbourg, CNRS/IN2P3
R. Bayes, University of Glasgow
P. Bernardini, Università del Salento and INFN, Sezione di Lecce
A. Bernstein, Lawrence Livermore National Laboratory
A. Bertolin, INFN, Sezione di Padova
S. Bhadra, York University
M. Bishai, Brookhaven National Laboratory
V. Blackmore, Oxford University
A. Blondel, University de Geneve
E. Blucher, University of Chicago
S.A. Bogacz, Thomas Jefferson National Accelerator Facility
C. Booth, University of Sheffield
N.S. Bowden, Lawrence Livermore National Laboratory
S.B. Boyd, University of Warwick
A. Bravar, University de Geneve
S.J. Brice, Fermi National Accelerator Laboratory
A.D. Bross, Fermi National Accelerator Laboratory
R. Brugnera, INFN and Università di Padova
C. Bryan, Oak Ridge National Laboratory
L. Bugel, Massachusetts Institute of Technology
A. Bungau, University of Huddersfield
F. Cadoux, University de Geneve
L. Calabretta, INFN-LNS, Catania
A. Calanna, Massachusetts Institute of Technology
L. Camilleri, Columbia University
D. Campo, Massachusetts Institute of Technology
F. Cavanna, Yale University
H. Cease, Fermi National Accelerator Laboratory
S. Cecchini, INFN, Sezione di Bologna
L. Celona, INFN-LNS, Catania
A. Cervera, Instituto de Fisica Corpuscular, CSIC and Universidad de Valencia
H. Chen, Brookhaven National Laboratory
M. Chernyavskiy, Lebedev Physical Institute of Russian Academy of Science
J.C. Cherwinka, University of Wisconsin
E. Church, Yale University
D. Cianci, University of Chicago
T. Classen, Lawrence Livermore National Laboratory
J. Cobb, Oxford University
G. Collin, Massachusetts Institute of Technology
D. Colling, Imperial College London
P. Coloma, Center for Neutrino Physics, Virginia Tech
L. Coney, University of California, Riverside
J.M. Conrad, Massachusetts Institute of Technology
O. Dalkarov, Lebedev Physical Institute of Russian Academy of Science
G. De Geronimo, Brookhaven National Laboratory
M. De Serio, INFN and Università di Bari
D. Dean, Oak Ridge National Laboratory
D. Di Ferdinando, INFN, Sezione di Bologna
Z. Djurcic, Argonne National Laboratory
A. Dobbs, Imperial College London
J. Dobson, Imperial College London
M.J. Dolinski, Drexel University
A. Donini, Instituto de Fisica Corpuscular, CSIC and Universidad de Valencia
U. Dore, Università di Roma
P. Dornan, Imperial College London
M. Dracos, IPHC, Université de Strasbourg, CNRS/IN2P3
F. Dufour, University de Geneve
S. Dusini, INFN, Sezione di Padova
R. Edgecock, STFC Rutherford Appleton Laboratory
Y. Efremenko, Oak Ridge National Laboratory and University of Tennessee
A. Ereditato, University of Bern
J. Evans, The University of Manchester
R.A. Fini, INFN, Sezione di Bari
B. Fleming, Yale University
W.M. Foreman, University of Chicago
A. Galindo-Uribarri, Oak Ridge National Laboratory
S. Gammino, INFN-LNS, Catania
A. Garfagnini, INFN and Università di Padova
D. Garisto, Columbia University
G. Garvey, Los Alamos Natioanl Laboratory
M. Geelhoed, Fermi National Accelerator Laboratory
M.A. George, Imperial College London
T. Ghosh, Instituto de Fisica Corpuscular, CSIC and Universidad de Valencia
G. Giacomelli, INFN and Università di Bologna
A. Glenn, Lawrence Livermore National Laboratory
J.J. Gomez-Cadenas, Instituto de Fisica Corpuscular, CSIC and Universidad de Valencia
M. Green, Oak Ridge National Laboratory
R. Guenette, University of Oxford
R. Gutierrez, University of California, Los Angeles
A. Haesler, University de Geneve
S. Hans, Brookhaven National Laboratory
G. Hanson, University of California, Riverside
P.F. Harrison, University of Warwick
M. Hartz, York University
K.M. Heeger, Yale University and University of Wisconsin
R. Henning, University of North Carolina and Triangle Universities Nuclear Laboratory
P. Hernandez, Instituto de Fisica Corpuscular, CSIC and Universidad de Valencia
J.A. Hernando Morata, Universidade de Santiago de Compostela
J. Ho, University of Chicago
P. Hodgson, University of Sheffield
L. Hu, Brookhaven National Laboratory
P. Huber, Center for Neutrino Physics, Virginia Tech
C.M. Ignarra, Massachusetts Institute of Technology
A. Izmaylov, Instituto de Fisica Corpuscular, CSIC and Universidad de Valencia
K. Jakovcic, Rudjer Boskovic Institute
C. James, Fermi National Accelerator Laboratory
C.M. Jen, Center for Neutrino Physics, Virginia Tech
R.R. Johnson, Best Cyclotron System, Inc.
R. Johnson, University of Cincinnati
B.J.P. Jones, Massachusetts Institute of Technology
L.M. Kalousis, Center for Neutrino Physics, Virginia Tech
Y. Kamyshkov, University of Tennessee
Y. Karadzhov, University de Geneve
G. Karagiorgi, Columbia University
W. Ketchum, Los Alamos National Laboratory
B. Klicek, Rudjer Boskovic Institute
T. Kobilarcik, Fermi National Accelerator Laboratory
A. Kolano, University of Huddersfield
J. Kopp, Max Planck Institut für Kernphysik, Heidelberg
L. Kormos, Lancaster University
A. Korzenev, University de Geneve
U. Kose, INFN, Sezione di Padova
I. Kreslo, University of Bern
V.A. Kudryavtsev, University of Sheffield
Y. Kuno, Osaka University
A. Kurup, Imperial College London
P. Kyberd, Brunel University
F. Labrecque, Best Cyclotron System, Inc.
J.B. Lagrange, Kyoto University
A. Laing, Instituto de Fisica Corpuscular, CSIC and Universidad de Valencia
C. Lane, Drexel University
T.J. Langford, Yale University
J.G. Learned, University of Hawaii
J.M. Link, Center for Neutrino Physics, Virginia Tech
I. Lippi, INFN, Sezione di Padova
D. Lissauer, Brookhaven National Laboratory
B.R. Littlejohn, University of Cincinnati
A. Liu, Indiana University Bloomington
W. Loinaz, Amherst College
K. Long, Imperial College London
A. Longhin, Laboratori Nazionali di Frascati dell'INFN
W.C. Louis, Los Alamos National Laboratory
P. Loverre, Università di Roma
K. Mahn, TRIUMF
M. Malenica, Rudjer Boskovic Institute
G. Mancarella, Università del Salento and INFN, Sezione di Lecce
G. Mandrioli, INFN, Sezione di Bologna
C. Mariani, Center for Neutrino Physics, Virginia Tech
J. Maricic, University of Hawaii
G. Marsella, Università del Salento and INFN, Sezione di Lecce
C. Martin, University de Geneve
J. Martin, University of Toronto
N. Mauri, Laboratori Nazionali di Frascati dell'INFN
K. Mavrokoridis, University of Liverpool
N. McCauley, University of Liverpool
K.T. McDonald, Princeton University
E. Medinaceli, INFN and Università di Padova
O. Mena, Instituto de Fisica Corpuscular, CSIC and Universidad de Valencia
S. Menary, York University
M. Mezzetto, INFN, Sezione di Padova
G.B. Mills, Los Alamos National Laboratory
R. Mingazheva, Lebedev Physical Institute of Russian Academy of Science
S.R. Mishra, University of South Carolina
N. Mokhov, Fermi National Accelerator Laboratory
J. Morfin, Fermi National Accelerator Laboratory
Y. Mori, Kyoto University
S. Morrell, Idaho National Laboratory
Z. Moss, Massachusetts Institute of Technology
M.T. Muciaccia, INFN and Università di Bari
S. Mufson, Indiana University
H.P. Mumm, National Institute of Standards and Technology
W. Murray, STFC Rutherford Appleton Laboratory
M. Nessi, CERN
D. Neuffer, Fermi National Accelerator Laboratory
R. Nichol, University College London
J.S. Nico, National Institute of Standards and Technology
E. Noah, University de Geneve
H. Okuno, RIKEN
O. Palamara, Yale University
M.A. Palmer, Fermi National Accelerator Laboratory
A. Paoloni, Laboratori Nazionali di Frascati dell'INFN
V. Papavassiliou, New Mexico State University
S. Parke, Fermi National Accelerator Laboratory
S. Pascoli, Institute for Particle Physics Phenomenology, Durham University
J. Pasternak, Imperial College London
A. Pastore, INFN, Sezione di Bari
L. Patrizii, INFN, Sezione di Bologna
Z. Pavlovic, Los Alamos National Laboratory
N. Polukhina, Lebedev Physical Institute of Russian Academy of Science
M. Popovic, Fermi National Accelerator Laboratory
M. Pozzato, INFN and Università di Bologna
X. Qian, Brookhaven National Laboratory
L. Qiuguang, Los Alamos National Laboratory
V. Radeka, Brookhaven National Laboratory
R. Rameika, Fermi National Accelerator Laboratory
P. Ratoff, Lancaster University
M. Ravonel, University de Geneve
H. Ray, University of Florida
M. Rayner, University de Geneve
S. Ricciardi, STFC Rutherford Appleton Laboratory
M. Roda, INFN and Università di Padova
B. Roe, University of Michigan
T. Roganova, Lomonosov Moscow State University
C. Rogers, STFC Rutherford Appleton Laboratory
E. Romero, Oak Ridge National Laboratory and University of Tennessee
G. Rosa, Università di Roma
C. Rosenfeld, University of South Carolina
P. Rubinov, Fermi National Accelerator Laboratory
C. Rudolf von Rohr, University of Bern
Z. Sahnoun, INFN, Sezione di Bologna
E. Santos, Imperial College London
A. Sato, Osaka University
E. Scantamburlo, University de Geneve
D.W. Schmitz, University of Chicago
J.K. Sedgbeer, Imperial College London
T. Sen, Fermi National Accelerator Laboratory
M.H. Shaevitz, Columbia University
T. Shchedrina, Lebedev Physical Institute of Russian Academy of Science
I. Shimizu, Tohoku University
S. Simone, INFN and Università di Bari
M. Sioli, INFN and Università di Bologna
C. Sirignano, INFN and Università di Padova
G. Sirri, INFN, Sezione di Bologna
M. Skuhersky, University of California, Los Angeles
D.R. Smith, Brunel University
P.J. Smith, University of Sheffield
P. Snopok, Illinois Institute of Technology
J.T. Sobczyk, Institute of Theoretical Physics, University of Wroclaw
L. Søby, CERN
M. Soderberg, Syracuse University
S. Soldner-Rembold, The University of Manchester
F.J.P. Soler, University of Glasgow
M. Sorel, Instituto de Fisica Corpuscular, CSIC and Universidad de Valencia
J. Spitz, Massachusetts Institute of Technology
N. Spooner, University of Sheffeld
M. Spurio, INFN and Università di Bologna
P. Stamoulis, Instituto de Fisica Corpuscular, CSIC and Universidad de Valencia
L. Stanco, INFN, Sezione di Padova
I. Stancu, University of Alabama
N. Starkov, Lebedev Physical Institute of Russian Academy of Science
M. Stipcevic, Rudjer Boskovic Institute
T. Strauss, University of Bern
S. Striganov, Fermi National Accelerator Laboratory
A. Surdo, INFN, Sezione di Lecce
A.M. Szelc, Yale University
H.A. Tanaka, The University of British Columbia
R. Tayloe, Indiana University
C.E. Taylor, Los Alamos National Laboratory
I.J. Taylor, University of Warwick
M. Tenti, INFN and Università di Bologna
K. Terao, Columbia University
S.J. Thompson, Idaho National Laboratory
L. Thompson, University of Sheffield
M. Thomson, University of Cambridge
C. Thorn, Brookhaven National Laboratory
M. Toups, Massachusetts Institute of Technology
C. Touramanis, University of Liverpool
C.D. Tunnell, NikHEF, Amsterdam
Y. Uchida, Imperial College London
R.G. Van De Water, Los Alamos National Laboratory
N. Vassilopoulos, IPHC, Université de Strasbourg, CNRS/IN2P3
M. Vladymyrov, Lebedev Physical Institute of Russian Academy of Science
W. Wang, College of William and Mary
M.O. Wascko, Imperial College London
M. Weber, University of Bern
B. White, Oak Ridge National Laboratory
D. Whittington, Indiana University
E. Wildner, CERN
M.J. Wilking, TRIUMF
R.E. Williams, National Institute of Standards and Technology
D. Winklehner, Massachusetts Institute of Technology
L.A. Winslow, University of California, Los Angeles
W. Winter, Universität Würzburg Am Hubland
T. Wise, Yale University
J.J. Yang, Massachusetts Institute of Technology
U.K. Yang, The University of Manchester
M. Yeh, Brookhaven National Laboratory
B. Yu, Brookhaven National Laboratory
N. Zaitseva, Lawrence Livermore National Laboratory
G. Zeller, Fermi National Accelerator Laboratory
J. Zennamo, University of Chicago