higgs - page 32

12. Thomas Jefferson National Laboratory (USA)
A moderate-energy ~5.7-GeV! electron accelerator, this
machine studies interactions with nuclei and the photopro-
duction and electroproduction of resonances containing light
quarks (u , d , s ), with an eye to seeing those that cannot be
explained purely as qq¯ mesons or qqq baryons. An upgrade
to 12 GeV is under discussion.
280. ‘‘Measurements of the Cross Section for e1e2→ hadrons at Center-
of-Mass Energies from 2 GeV to 5 GeV,’’ BES Collaboration, J. Z.
Bai et al., Phys. Rev. Lett. 88, 101802 ~2002!. ~I!
281. ‘‘Observation of High-Energy Neutrino Reactions and the Existence
of Two Kinds of Neutrinos,’’ G. Danby et al., Phys. Rev. Lett. 9,
36–44 ~1962!.
282. ‘‘Further Evidence for the Decay K 1→ p1 nn¯ ,’’ BNL E787 Collabo-
ration, S. Adler et al., Phys. Rev. Lett. 88, 041803 ~2002!. ~I!
283. ‘‘Precise Measurement of the Positive Muon Anomalous Magnetic
Moment,’’ BNL E821 Collaboration, H. N. Brown et al., Phys. Rev.
Lett. 86, 2227–2231 ~2001!. ~I! An updated version of this result has
appeared recently with roughly half the experimental error: ‘‘Mea-
surement of the Positive Muon Anomalous Magnetic Moment to 0.7
ppm,’’ BNL E821 Collaboration, G. W. Bennett et al., Phys. Rev.
Lett. 89, 101804 ~2002!; 89, 129903~E! ~ 2002!. See http://
phyppro1.phy.bnl.gov/g2muon/index.shtml for latest
details.
284. ‘‘Experimental Observation of the Intermediate Vector Bosons W1,
W2, and Z 0, C. Rubbia, 1984 Nobel Lecture, available at http://
www.nobel.se/physics/laureates/1984/rubbia-
lecture.html. ~I!
285. ‘‘Stochastic Cooling and the Accumulation of Antiprotons,’’ S. Van
Der Meer, 1984 Nobel Lecture, available at http://
www.nobel.se/physics/laureates/1984/meer-
lecture.html. ~I!
286. ‘‘Review of final LEP Results or a Tribute to LEP,’’ J. Drees, in
Proceedings of 20th International Symposium on Lepton and
Photon Interactions at High Energies „Lepton Photon 01…, ~Ref.
3!, pp. 349–373. ~I!
287. ‘‘From LEP to LHC, a Review of Results and a Look to the Future,’’
L. Foa`, Nucl. Phys. Proc. Suppl. 75A, 28–36 ~1999!. ~I!
288. ‘‘A Personal History of CESR and CLEO,’’ K. Berkelman, Cornell
University report CLNS 02/1784 ~unpublished!. ~I!
289. ‘‘CLEO-c and CESR-c: A New Frontier in Weak and Strong Interac-
tions,’’ I. Shipsey, in Proceedings of 9th International Symposium on
Heavy Flavor Physics, Pasadena, California, 10–13 Sept. 2001, AIP
Conf. Proc. 618, 427–437 ~2002!. ~I!
290. ‘‘The First Large-Scale Application of Superconductivity: The Fermi-
lab Energy Doubler, 1972–1983,’’ L. Hoddeson, Historical Studies in
the Physical and Biological Sciences 18, 25–54 ~1987!.
291. ‘‘Observation of nt Interactions,’’ DONUT Collaboration, K.
Kodama et al., Phys. Lett. B 504, 218–224 ~2001!. ~I!
292. ‘‘Total Cross-Sections of p1, K 1 and p on Protons and Deuterons in
the Momentum Range 15-GeV/c to 60-GeV/c,’’ S. P. Denisov et al.,
Phys. Lett. 36B , 415–421 ~1971!. ~I!
B. Nonaccelerator experiments
1. Underground or underwater laboratories
The ability to perform experiments in a low-background
environment is greatly increased by going deep underground,
where cosmic ray interactions are less frequent. A number of
major laboratories now are operating underground, including
ones at the Kamioka mine ~ Japan!,293 Gran Sasso ~Italy !, 294
and Soudan ~Minnesota, USA!.295 Whereas the focus of sev-
eral laboratories initially had been the search for proton de-
cay, it has now broadened to include the study of interactions
of neutrinos from atmospheric cosmic rays, the Sun, and
even supernovae, and the search for effects of dark matter.
The next stage of operation of detectors in the laboratories
mentioned above includes the study of artificially produced
neutrinos. The Fermilab accelerator will send neutrinos to
the MINOS detector296 in Soudan. The proton synchrotron at
KEK in the K2K experiment,293 and later a machine known
as the Japan Hadron Facility,297 will direct neutrinos to the
SuperKamiokande detector in Kamioka. Finally, a detector
known as KamLAND,298 also in the Kamioka mine, will be
sensitive to neutrinos from reactors over a large portion of
Japan, and has already reported its first results.261 Some cur-
rent and forthcoming detectors will also be sensitive to natu-
rally occurring neutrinos. These include the Sudbury Neu-
trino Observatory in Ontario,299 the Borexino experiment300
in Gran Sasso, and the SuperKamiokande detector men-
tioned above. At the South Pole a number of phototubes have
been sunk deep into the ice in the AMANDA experiment,301
which is envisioned in the IceCube experiment302 to expand
to an effective volume of a cubic kilometer. The RICE
experiment303 seeks to study the low-frequency tail ~at sev-
eral hundred MHz! of Cˇ erenkov emission by electrons pro-
duced by neutrinos, also in South Polar ice. A number of
neutrino detectors are also deployed or planned deep under-
water, e.g., in Lake Baikal304 and the Mediterranean Sea
~ANTARES,305 NEMO,306 NESTOR307 !.
2. Atomic physics
A large accelerator is not always needed to study funda-
mental particle physics beyond the standard model. An ex-
ample is the window on non-standard physics provided by
atomic parity violation. ~See the bibliography in Ref. 72.!
Studies of weak-electromagnetic interfence in atoms such as
Cs, Tl, and Pb are in principle sensitive to new interactions
and extended gauge theories, particlarly if the effects of
atomic physics can be separated from more fundamental ef-
fects.
3. Electric and magnetic dipole moments
The electric dipole moment of the neutron is an excellent
probe of physics beyond the standard model, which predicts
it to be orders of magnitude smaller than its current upper
bound243 of u d nu , 6 3 10226e cm. For a bibliography of ex-
perimental literature on electric dipole moments and atomic
parity violation, see Ref. 72.
The magnetic dipole moments of particles also provide
important constraints on the Standard Model. The anomalous
magnetic moment of the muon, in particular, is sensitive to
new-physics effects such as those that arise in some versions
of supersymmetry.308 The current status of measurements of
this quantity indicates a possible deviation from standard-
model predictions, but at a level which is not yet statistically
compelling.283
293. See the web page http://www-sk.icrr.u-tokyo.ac.jp/.
294. See the web page http://www.lngs.infn.it/.
295. See the web page http://www.hep.umn.edu/soudan/.
296. See the web page http://www-numi.fnal.gov/.
297. See the web page http://jkj.tokai.jaeri.go.jp/.
298. See the web page http://www.awa.tohoku.ac.jp/html /
KamLAND/.
299. See the web page http://www.sno.phy.queensu.ca/.
300. See the web page http://pupgg.princeton.edu /
;borexino/.
301. See the web page http://amanda.berkeley.edu/amanda/.
302. See the web page http://icecube.wisc.edu/.
303. See the web page http://kuhep4.phsx.ukans.edu/
;iceman/.
317 317 Am. J. Phys., Vol. 71, No. 4, April 2003 Jonathan L. Rosner