1111111~/11'~I~~l~i~l~~ij~I'1~~~II~ o llbD 0026270 3 The yeiU' 1993 il a. b&nner anniveuary ior our understanding of nature: it marks the 10th anniversary of the di.covery of the ca.rriera of the Weak force: the Wand Z particles at CERN, the laboratory near Geneva, Switzerland; the 20th anniversary of the discovery of Weak Neutral Currents in Nature: a Thirty Year the Weak Neutral Currents, and the 30th anniversary of the first revealing but null searches Retrospective· for Weak Neutral Currentl that change the Quark Family! All of these developments have left a profound mark on our study of the most fundamental aspects of nature: "the Elementary Particles and their Forces". These observations helped develop the foundation David B. Cline of the Standard Model of Elementary Particles. This article is a partial cele~ration of this Center for Advanced Accelerator anniversary and an attempt to peer into the future implications and gain a 'perspective 011 Department.! of Phllsia & Astronomy these accomplishment.. A. in the telling of the history of any human accomplishments. University of California Los Angdes it will appear more logical than when it actually occurred. We wiU also describe how .. OS Hilgard Avenue, Los Angeiu, CA 900f"-15"7, USA the intervening yean have taught UI the way in which Neutral Currents contribute to A.trophysic. and the ExplOlion o( Supernova, wiU help in future possible break.throu!1;hs UCLA-PPH0052-8/93 2 -0 in the study of Elementary Particles and possibly even the very nature of life on Earth: the double helix structure of DNA, present in all life forms! It can now be said the there have been three major advances in Physics during the Ab,tract past 100 or so yean. The Theory of Relativity can be dated as taking place during 190.'5. Neutral Currentl play an important role in nature. We trace the early history of 1919: the development of Quantum Mechanics between 1913-1930: the experimental anu Neutral Char~ed Weak Current studia from tbe 1930'. to the dilcovery of the Wand Z theoretical formulation of the Standard Model of Elementary Particles ( ruse of the Standard in 1983. In the 1960's the null search (or Neutral CUrrenti that chan~e Family combined Model), which began around 1960 and continued until approximately 1983. Of course, there with modell of Weak Neutral and Char~ed Currentl and led to the concept of Natural have been many other important advances in Nuclear Physics, Condensed Matter Physics, family Conaervation in Neutral Cunentl. In rapid order: Weak Neutral Currents Cosmology and so forth. However, the three advances mentioned above are distinguished (WNC) were discovered in 1973, were well understood by 1978 and were followed by the di.covery o( the Wand Z in 1983. Neutral Currentl (NC) are important in Supernova by having led to a nearly complete picture of to major area of fundamental science that has ExploeioRi and the Early Univene. The March (or NC that chan~e Family extend. our stood the telt of tIme and verification by many experiments. The period of the " ltise ur study o( the subatomic world into the incredible range o( 100TeV and it on-going today. the Standard Model" was full of major theoretical and experimental discoveries. t\mong The super colliders. SSC at Dallu, USA, &lid LHC in Geneva. SwiLlerland, will allow the mOlt important event. during this period Wal the discovery of Neutral Currents (NC) us to ex~nd thit March considerably. in 1973. AU thr~ of the break-through mentioned above have one thing in common: the basic 1 The Early Concepts of the !VB and Neutral Currents theory has been greatly tested by experiment very early. For General Relativity the observed deflection of Starlight by the Sun in 1919 was a crucial experiment. For the Quantum Theory As is weU known, the weak intera.ction wu a.ccidentally discovered by H. Beckerel in 1896 it was the study of various Atomic Physics systems as weU as the observation of the particle. when he pla.ced Uranium and a photographic emulsion in the same drawer only to observe like nature of light (Compton Effect) and the wave like-nature of matter (2·Slit Electron the emulsion had become expOied. This wu the discovery of the charged current weak Interference Pattern). For the Standard Model of Elementary Particles the key period of interaction. It took 77 ye&rl longer to discover the neutral current weak interactions in experimentation was between 1974 and 1978. It was during this period that the newly 1!J73. In the intervening yean there were repeated suggestions that there could be a neutral discovered Neutral Currents were quickly confirmed and studied in numerous experiments current interaction. The earliest explicit suggestion leems to have been made by Gamov around the world. Given the breadth of the physical phenomena involved, this was a truly and TeUer in 1937. In the 1950's and 1960's there were many modea of the weak force that remarkable period. included a neural component. In Fig. 1 we illu.trate many of the proposals for extensions To tra.ce the history of the Weak interaction, it is necessary to place particular emphasis of the WeiLk Interaction and the Intermediate Vector Boaon (IVB) concepts.[IJ on the discovery of NC and the underlying theory of the Standard Model. The impa.ct of After the point intera.ction of Fermi in 1932, the first attempt to unify the charged and the discovery of NC on our understanding o( nature could turn out to be as important as neutral current intera.ction seems to ha.ve been carried out by Oscar Klien in H138. However, that of the Weak Intera.ction or Radioactive Decay, which was discovered uy If. Bequercl the real search for WNC started in the early 1960's in rare l\ decays[2J. As illustrated in in 1896, and which we now know to be a Charged Current interaction in contrast to the Fig. I, there were many theore~ical models that suggested that neutral currents may exist. Neutral Current. By 1933, thirty-seven years later, the source of the ener~y of the Sun was Thus, there was no reallaclc of motive to sea.rch for WNC but a strong general theoretical shown to come from the Weak Interactions by Hans Bethe of Cornell Univp.rsity. i1lustratinc; prejudice against the search. In Fig. 2 I attempt to give a history of the search and discovery the great sigruficance of that d:scovery. of various forms of neutral currents[lJ.
oPrf!pued for the EPS9 Trend. in Phy.ics ConCereBce, Florence. September 1993.
r? 1 The concept of flavor wu not weU undentood in the early and mid 1960. anu it appt'ared 2 The Search for WNC's in the 1960'. chat u good a technique U &ny to learch for WNC wu to study rare h' uecaYI. One ur the earliest experiment. set a Limit o( '" 10-8 on tn T.i.ble 1 we report the importa.nt milestones for the lUrch for WNC in the 1960'5[lJ. There were many zigl &lid Zagl in the aearch due to the &reat difficulty of refiecting varioul K+ - ",+ e+ e- backgrou ndl. In 1963 a CERN neutrino KToup publiahed a very low limit on WNC from their neutrino The Limitl on FCWNC were lummarized in a report I wrote in 1967 (Fig. 3b). which experiment of 0.03 (CERN Group, PhYlia Letters, 1964)[3J. See Fig. 3a (reproduced from included K - IJIJ and the search K+ -- '/1'+ vv from my early work/31. the original article). Thil incorrect result diminished the prospectl for detecting WNC and In 1965 - 1970 a crucial seuch for discouraged some group. (iDcluding a Wi.co.wn heavy liquid bubble chamber group) from search.ing for WNC in other propoMd neutrino experiment.. On the other hand. WNC K+ -- ,..+ vv could have been discovered in 1964. thu. altering the hi.tory in thll field considerably. wu . tarted. Thi. search wu a pure fCWNC process whereas all other searches had charged The null resultl o( the WNC search reinforced much of the theoretical prejudice o( the particlel in the final Itate and may have been affected by electromagnetic interactions. as time. once again Ihowing that IOmetimes experimentaliat. rely too heavily on the guidance some people claimed. The history of the search for this decay mode is given in Fig . ·Ia.: it of theory. On the other hand the .ea.rch for WNC In the HPWF experiment benefited from continues today (see Fig. 4b as weU)[3. 7J. S. Weinbergs advice. and it was for that reuon that an "energy" trigger was installeu ill By 1970 the incorrect CERN limit on WNC and the extremely strong Limits on FCWNC mid 1972 in that experiment. caused most people to believe that neutral currents did not exist in nature. The GtM model However, even after the Weinbe~-S alam Model wu gaining acceptance the null results wu invented and showed that on WNC searches continued. In Fig. 3b I .how the early limits on exclusive WNC channels up to 1972, when the limit. were still well below the now measured values. This illustrates 1. FCWNC could be suppressed in certain models how difficult the discovery o( WNC really wuflJ! 2. A hadron-lepton symmetry existed. 3 The Significance of the Search for FCWNC in the 1960's Today, the GIM mechani.m has only been tested for light quarks. Charm and B quarks are a rich ground in which to continue the search for FCWNC and the search for FCWNC The concept of flavor was not well understood In the early and mid 1060'. and it appeared haa started there[8J. that as good a technIque at any to search (or WNC wu to study rare K decays. One of 8 the earliest experiments set a Limit of"" 10- on[4J 4 The 1973 Period: The HPWF Experiment
J(+ - 1'+ e+ e- In 1973 the HPWF experiment at fNAL turned on[9). Almost at the start '1J·less· neu The Limits on FCWNC were summarized in a report I wrote in 1967 (see Fig. 4a). which trino events were ob.erved. Rumors of similar events at CERN set into motion an intense incl uded K - IJI-' and the &earch K+ - '11'+ vii (rom my early work[5J. competition[10J. The HPWF group actually performed 2 complete experiments in 1973 In 1965-1970 a crucial search for a.nd, after considerable confusion. the issue was (ully ,resolved by December of that year. The early limit on WNC and the strong limits on FCWNC played a role in the H PWF [(+ .... 1'+ vii groupi confulion. However, along with the GGM evidence, the existence of WNC was fully established at thi. point. in 1973! The book and reports by Peter Galison gives an accurate was started. This search wu a pure FCW NC process, whereu all other searches had charged Account o( thil period of hi.tory. in my opinion[1l]. particles in the final state and may have been affected by electromagnetic interaction, as By 1973, when the Fermi National Accelerator Laboratory (FNAL) neutrino beam was some people claimed. The history of the ..arch (or this decay mode is given in Fig. 4b; it jUlt being cornmi8lioned and a luge detector built by the experimental groups from Harvard. continues today (see Fig. 41. at well)[I. 4]. Penn and Wisconsin (HPW). the very luge bubble chamber. GargameUe. was taking corious By 1970 the correct CERN limit on WNC &lid the extremely strong Limits on FCWNC data at CERN: the illue o( the existence of NC was coming to a boil! It was in this year. caused most people to believe that neutral current. did not exist in nature. The GIM model starting with Gargamelle and the HPW experiments. that NC were observed (see Ta.ble 1) . was invented and showed that[6] I was privileged to be the spokesperson for the HPW experiment and have the opportunity to live through the trials and tribulations of t he discovery of neu tral curren ts. hay ing created 1. FCWNC could be suppressed in certain models some o( them myself. The other senior members of the HPW team were A.K. ~1ann of Penn 2. r\ hadron-lepton symmetry existed and C. Rubbia of Harvard. The discovery o( NC was not easy and the two experimental groups that were involvf'd Toda.y the GIM mechanism hu only been tested (or Light quarks. Cho nn and n quarks are in the action in 1973 were anyth.ing but placid. In contrast. the early search for WNC a rich ground in which to continue the search (or FCWNC and the search (or FCWNC has was plagued with incorrect but placid results as recorded in Table 1. There were rll mors ~tarted there. 3 -t :In<1 rumon or rumon, pu.ing back and (orth &CrOi. th. Ati&Dtic b.tween Batavia, iilinoil l.,v-e: of piei:iiiOi'i ... LEP _itG th:.i: be va.!:.::.b!c to ~ea:"ch fc~ phy~ : c" b~y c n<.! the st a nd~!"d ( II P W) to Geneva, Switzerland (GarS&melle). Some ot the rneaas" were even being curled model. by members of one or the other team, .inee both sroup. had an international constitution. The first to report a pOlitive result wu the Ga.rgamelle Bubble Chamber group. But the HPW group'. fint data twng in 1973 .howed a very la.rge excess of the NC events and 6 The Future an early scientific paper wu sent to a journal a few days after that of Its European rival. The future study of elementa.ry pa.rticlel depends partia.lly on two (actors: (1) the detailed Unfortunately, the paper lent by the HPW group wu returned by the pa.per's referee for and preci.e meuurements qf NC puarneters and (2) the continued search FCNC. LEP clarification, ~ t hough it wu Ia.ter publi. hed. in Geneva., Switzerland, i. being used to study the ZO by the millions and, has improved During the discovery period of 1973, a complex set of event. occurred. Fig. 2 shows an our knowledge of the NC pa.rameteu. The key to future mea.tlurements are:, the Radiative attempt to represent this sequence. For a more complete description one can recommend the Correction. to the Standa.rd ModeJ. So far, IlQ direct evidence for Radiative loop corrections book and various a.rticles by Peter Galison, who hu made a careful study of the historical haa been obtained from the several million ZO studied at LEP, Fig, 630 shows the kind of events. tools that will be used in the future to refine these measurements. Dy the year ',WOO, sin~ B,u may be known to better than four decimal points, an incredible accomplishment in 25 years 5 The Period Between 1973 -1983 of study! The sea.rch for Neutral Currents that change Quark Flavor (FCNC) is also enterin g in to During the period between 1973-1977 an incredible .ynthesis occurred. The value of a sensitive period. Fig. 6b shows one such experiment where the b ( Beauty) q ll ark lo 5 (S trange) qua.rk transition sinl9W = 0.25 ± 0.04, " + XO (I) consistent with the present data from LEP of '-i+l
lin 1 9w = 0.230 ± 0.002 is being searched for. We can consider the XO particle to indicate a new level of suustruclurc in physics. The most senlitive search to da.te was carried out at the CERN pp collid er by the was measured. All the data was described by two pa.rameters, sinl 9w and p, and many authors group [13J. The current limits in FCNC are shown graphicaily for several important different types of data were involved. Fig. S gives an account of this period by the value of processes in Fig. 6c and 6d. The other interesting FCNC process (s quark to d ( Down ) sinz Ow that was being mea.sured[l]. quark) In 1977 parity violation in atoms wu di.covered at NovOlibink and in 1978 at SLAC. The full SU(2) X U(l) model had been accepted by the hlgh energy community by 1978. d + X O ('2 ) Thus, in a four year ... eriod WNC were under.tood whereu the correaponding understanding '- /I + Ii of charged currents took more than 30 yean. can be sea.rched for by the reaction In 1976 an idea wu put forwud by C. R.ubbia of CERN, P. McIntyre of Texas A&' M and the author to convert either the CERN or FNAL Synchrotron to a proton·antiproton h'+ ",+ + /I + ii (3) collider in order to discover the W a.nd Z partldeI[12}. In 1983 the W and Z were discovered at CERN, the pinnacle of the Rise of the Stand&rd Model! Thi. sea.rch wa.s started in 1965 by the author in order to search for a clean example of While the p&r&metera of WNC were being under.tood in the incredible period of just FCNC and continues today (see Fig. 6c). The level of sensitivity to the mass of the .Yu 3 - .. years, several of us st&rted to plan how to detect the Wand Z bosons. The pp coUider particle has now re&ehed well beyond 10TeV, the Superconducting Super Collider (SSC ) idea had been born in 1976 and the Wand Z di.covered in 1983. (Some of the members of energy. Future experiments can extend the range to 100 and even possibly 1000TeV, far the HPWF team were pa.rt of that discovery.) beyond that available to the SSC or LHC Super Colliders. Fig. 630 and b show the history During the period of 1975-1978 the value of .in2 9wstabLized to the level of 0.22-0.25, of the limits on the search for FCNC both in the rates (b) and amplitudes (a)[ 13 ). implying a mass of the W and Z in the range of (78,85) and (82,92) GeV (see Fig. 5). At While the earliest searches for Flavor Changing Neutral Currents used the decay of t rus point it wu realized by Cline, Rubbia and McIntyre that a tiP collider, with the center K mesons and failed to observe neutral currents, we now know that these null results of mass energy of 600GeV or greater, could be used to discover the Wand Z. which they are a key component of the Standard Model. In the simplest version there is a. sort of proposed. This concept wu carried out at CER.N where the Wand Z were discovered in Flavor Conservation built into the Neutral Currents which in turn prescribes that oill y 1983. (This wu the subject of another conference at UCLA in 1993.) two types of quarks should exist in nature: charges Q = -1 / 3 and Q = 2/3. In other The completion of the Rise of the Standard Model occurred during the period of 1974 words. one of the great successes of the Standard Model is the inabili ty to observe Neutral 1978, when the WNC paramei.era ainl 9", and p were measured in different reaction. and Currents thiLt change the Flavor of the Quark (Table 2)[lJ. In contrast. the observatloll found to be the aarne values within erron. The role of the null sea.rches for FCNC on the of even a tiny FCNC signal would imply structure beyond the Standard Model! Standard Model ia iUu.tra.ted in Table 2. The example of the measurement of sinl 9", is What can We hope to discover with such precise measurements of NC or searches for shown in Figs. 530 and 5b. Future studies of Atomic Parity Violation may reach the same FC NC: A process that goes beyond the Standard Model to possibly iUuminate the physics
)' r; Ta ble 1 w;uting tbere. We strongly bellev. ,ha.' ,h.r• • hould b. som. new lubstructure in the energy range from the W &nd Z to 'he Planck Scale, - lOI8GeV. AI illultrated In Fig. 7, t he Rise of the Standard Model had many pla.yerl. With the current excellent agreement between the LEP (5 million ZO's) and the Sta.ndud Model, the search for FCNC is even SOME MILESTONES IN THE SEARCH FOR WNC more important! (1962 - 1973) (D. CUne)!lJ References MILESTONES COMMENTS [IJ Proceedings o( the Intern. Symp. on 30 Year. of Neutral Currents: from Weak Neutral Currents to the (W)/ Z and Beyond, to be publilhed by AlP, editors D. CUne and A.K. 1962 BNL Neutrino Experiment Detects Strange events are likely incorrect ~fann; O. Klein, in Proc. Symp. on Lei NouveUes The de 130 Physique, Warsau. 1938 2nd Neutrino: Unusual Events associated with neutrons from (Illst. Int. de Cooperation InteUectueUe, Pa.ril, 1939), p. G; O. KI~in, Na.ture l!il1:l!.l7 noted in PhD students Thesis the shield ( 1948). (Little Crappers) [21 D. CUne, The Search for Weak Neutral Cummts, Proc. o( Ecol. Int. Hecg. Novi (196i), 1964 CERN Bubble Chamber Group(a) Reason for this incorrect limit and Thesis at Univ. o( Wisc. (1 965 ); U. Camerini, et aI., Phys. Rev. Lett. 1,1318 (1964). Reports a limit of 3% for WNC later given in 1970 paper [3J M.M. Block, et aI., PhYI. Rev. Lett. 12 (1964 ). 1967 E.C. Young Thesis at Oxford notes [~J U. Cameriru, et aI., PhYI. Rev. Lett.lJ318 (1964). Neutral Current-like Event.J exist in Data [5J D. CUne, The Search (or Weak Neutral Currentl, Proc. o( the Ecole Inter. Becg. Novi (1967), and the Thesis at Univ. of Wisconsin (1965). 1967 Large Hea.vy Liquid Bubble Chamber Gargamelle Bubble [61 S.J. G l~ho w, J. lliopuloul and L. Maia.ni, Phys. Rev. Dl1285 (1970). studied by the MURA-Wisc.·UCB Group Chamber already approved to Search (or WNC (II" - II,,) at ANL Incorrect CERN limits on WNC [7] J. Klems, et aI., Phys. Rev. Lett. 2i 1086 (1970). Later Proposed. (or BNL then Rejected! Discourage other Experimenters Proposed for BNL then Rejected! [8J S.L. Glashow, Nucl. Phys. 22. 579 (1961); S. Weinberg, Phys. Rev. Lett.ll1264 (1967); A. Salam, Proc. 8th Nobel Symp., Alpenugarden, 1986, ed. N. Svartholm. Pub. by 1969 HPW Experiment Proposed. Almqvilt and Wisell, STockholm, 1968, p. 367. '64 Limit on WNC Makes Search for Only Mention of Neutral Currents T his Process Difficult so (9J First report of the HPWF evidence (or WNC wu reported at, G. Myatt, Proe. of 1973 is for Leptoruc Processes Leptonic Processes Considered Bonn Conf., Germany (see Comment. In the question Iession); A. Benvenuti, et al., Phys. Rev. al 800 (1974) (submitted (or publ. Aug. 3, 1973) [this paper was returned 1970 CERN Group Rev ises '64 Lim it (b) by t he referee with questions; it wu no' withheld from publication; this was the first on WNC to '" 12% experiment by HPWF in early 1973J. 1972 Schwartz-Mann-SLAC Black Hole Too Few Events to make [iOJ Hasert, et aI., P hys. Lett. IH§ 138 (1973). Experiment finds Some Neutral Conclusi ve Arguments C urrent-like Events [IIJ P. Ga.l.i50n, How Experiments End, Univ. of Chicago Pres. (1987) and The Discovery o( Weak Neutral Currentl in 50 Yean of Weak Interactions, Proe. of the Wingspread 1972 Perkins Reports Limits on WNC Conf., Editors D. Cline and G. Rieduc:h, Univ. of Wise. Phys. Dept. Book (1984). Limit still Below at FNAL Meeting Currently Observed Values [i2J A. Benvenuti, et al., Phys. Rev. Lett ;n 189 (1976); C. Rubbia. P. Mcintyre. D. Cline, Proe. o( Aachen Neutrino Conf.. 1976 &nd subsequent reports by Cline. Rubbia and 1973 GargamelJe StruKgle with Large othel'1 (1976-80). HPW WNC Signal (see Ref. 12)
[13J D. Cli oe, The Search for Rare B Deay. a.nd B - BO Mixing, Pub. in the Proe. of (a) M. M. Block, et 0/. Phy•. Rev. Lett. J.! (196-1) lhe 3rd Topic.al Seminar on Heavy Fla.von, San Minia.to, Italy, 1991 and Proe. o( the (b) D. Cundy, et 01., PhYl. Lett. 3..1.lJ. -1 79 (19 70) meeting on Rare Band K Decay. and Novel Flavor Factories, AlP Book, July 1992.
} 8 Table 2
IMPACT OF FCNC SEARCH ON THE RISE OF THE STANDARD MODEL
PROCESS fWQ1l IMPLICATION
~+ d ..... 1963 FCNC Absent at first level of (K+ - lI'+vv) ..... 1970 Weak Interaction [GIM Mechanismj INTERMEDIATE VECTOR BOSON HISTORY Loop-j.d ..... 1960 - j4 New quark in Loo p, m, ..... 2 Ge V ,,+ ..., /\'0 _ 1\0, K!J - I\'L mixing (Charm) ..., ~ 16 (]'I ..... 1970's Natural Flavor Conservation for NC c (3 ,,+d 2 ~
Fig. 1: Intermedia.te vector boson his tory q EXPERIUENTAL HISTORY OF WEAK NEutRAL CURRENTS
H.'Nt C"II'"
'NNC i FeWHC ~. 110'(/\ IISM '. a.ten 1960, 1'01 11011101. ~ (:o.ea" 10 ClIfICt In I 1I0tllllq '" 1963 willi . 1(.- ...... Nucl.. Db,,1C1 D'Ouuet I
Mony ''''oretiCOI id." to, WNC ~ Other conclusions. A number of other fundamental pl aaa \ 1larti~ In 1!31-'~8 ) ".,y 11f1:~ ;i~~11 questions were discussed in our previous report I) all' It'- ..·IfV Ihal I ,ult aul first ora., FCWNC their present status is: Violation of muon number conservation
I G1M MtcftOflI1lll (1910) (ve f. vll ) < 1%; Violation of leptonic conservation < 6%
(f~.S = 0 1 nuctral current coupling / 6.5 = 0,
1961 -'61 GlasbOw-.....-Sala.. IIIOCIII charged current coupling) < 3%; Neutrino flip intensity / no neutrino flip intensity
]{ --. p, + Ve ocrt = < 1 10 I( --. p, + v" HPWF~_IOI.. ,.uaa ..... ,iqacl ' MOICI I A boson has been postulated which produces tl. Z •• Nri.....• lI.id...... ".. resonance of the type v + n --. l'V", --. p,- + p. If Im OOf,on. 10 conllnu. ll ZI DIId flit.,. uareft fot II,." QUO" sy'llm its properties are as predicted 10, 11 ) its mass IU"I moine by Ote.'73 \. - is > 5,5 GeV.
nOtri-- ~I 1/11 oiClulI
Fig. 3a: Limit on Weak Neutral Currents from the CERN G rou p (published in P hys. Letts., 1964) Fig. 2: Experimental hiltory or Weak NeunaJ Cutrents I')
.. Be.t Experimental Limit. on
Neutral Current K Decay, The Search for vP-'!l and lIup-!.!.1TN Upper Limit Procell _ \ - (CERN and 8NLJ Branching Couplin(C COD,tant 011 the Reference Ratio RatiO C.C. Ratio
1(+ - ",+e+e- < 8.8 X 10 -1. 4 gV (e+e- )/gv(e+ II.) 7 X 10- Cline. et a l.(~ · ';1 vJL --...... ~ (-) H P f(+-",+p+p- 3 x 10- 5 2 • • • vp - v~/ v.:J. -.un < gV (p+ p- )/gV (p+ IIjJ ) 1.4 X 10- Camerini. et aLI',' '-i-Oiscovery of Vp. P - V.:J. 7T ~ + ~ n ... K+ - ,..+vv < 1.1 X 10- 4 2 Before 1/' (WNC) or Slmllor gV (vv)/gV (e+ v.) 6 X 10- Cline(81 .15 < T. < 80~1t:\ v". + P - (J- - P7T r reaction K~ - p+p- 8 Di~!~ed ~ < 1.6 x 10- gA(p+p-)/gA(p+lljJ) i1 )( 10- 4 Bott ::..~It OJ f3odenhausen . t t CERN el 31. '. \ K? - p+p- < 7.3 X 10- 5 3 .=.~ VtL \ gA(p+ p- )/gA(p+ II,,) 1.6 x 10- [Jott V f3od enhausen, a:: 0.2 After WNC Oiscovereo eL al. K~ - ",op+p- No estimate gV (p+ p- )/gV (p+ II ) no estimate
",+e+e- K~ - No estimate gV (e+e- )/gV(e+ v.) no estimate 0.1 'lins talk 01 FNAl K+ - ",+ ",Oe+ e < 8 x 10-8 (R z<0.11 to 90% (L)] no estimate C line(dl J I" ( /{+ -. ",+p+e- f~Revisea in -1970 (O.Cunoy et 01) < 3 X lO-5 violates Cline(dl 01 I' . lepton conservation ~7 70 ~ 80 f{~ - p±e'f. < 9 x lO-5 violatM [lotL lepton Boden hausen, year conservation ct al .
• All estimates are 90% confidence limits
fig. 3b: CERN results (1967-1972) were well below the current and oblerved value of the Weak Neutral Current level after 1973-1974 Fig. 43,: The limits on Flavor Changing Weak Neutral Currrents from a [967 summary of D. Cline
"- 1-1 2 HISTORY OF THE VALUE OF SIN ew HI STORY OF THE SEA RCH FOR K+- TT' + tie ve DIR ECT
Numoer or K ~ in eloe nmenl - Experimenlal Limit 0. 35 Cline 2110- 4 2110! 81\1 ~ 4 3 Ixl0- Comeri ni et 01. B.C. ~ x10 5 Uttt tt 5.7110- 5Lju nq et 01. B.C. :..7110 \ 2 \_value 01 sin 8wwilh lime 3 1.41 lO··KltmS tt 01. 1.8110 0.30 o 7 3 9.4 I to· Coblt .t 01'7 1.1110 o ::::r V«t«t«(t5.6 110· • a: 10 Wand Z moss (C ern) ««t( 1.4 I to·' Asa no e l. 01. ~.5 x10 ~ at Q:) c: N c: v .;;; c:: o 0.25 1ft 85GeV -. loJ 11 -tt:M; ~6GeV - LEP RESULTS CD L~~~~~~~~ __Mw z82GeV -0 7. !l tOU ...! "w: 82G~~. _ 10-10 2~ M :92GeV t ~ ", If) z 0.20 "'+0 _ 1 ~ Th.o~ E CXl 2 . 7 110:~ Por ily violation +3: .. ~ (SL AC E!tlwrilllt'lItj :E 10-92 New Koon facility ? 1960 t970 19 80 1990 0,151 I I I I I I ! 73 75 77 "7r\ n. -- - 87 89 Year
Fig. 4b: Search for n: - ..vii-direet Flavor Chansinl Weak Neutral Currents
Fig. 5a.: The his tory of the value of sin1 elY
us 16 - ---Experimental limi ts ---- Loop Model UCU (1/+N -fL~x.l Effects with 6. Dbd(CESRl Level FCWNC 0.35 r-·------, \ 2 Various Modern Meosurements of si n 8 (M ) Dds .' • Ret.l1 w z z ~-liJ lO- r [1/ +10'10': T+e+e-(1963-6 4l] '\ (8°."8 Mix.ing 1
30 [D /D (UAll] 0. r ~"\ ..... ! bd bs \ ...... u cu Q. >< \ , ~ .:Ii. olo 17""10''' E , t \ K-fLfl- ...... Dbs 4 ~ .2 cu '0 z 10- r Dbdt Dbs N 0 ~ ~cu olo ~-----~ ~ 0.25r Dbd ~ : : 1• :/::. %:: = 1I:::::: : .- _._.1 a a asI a • a ...-... • ~- • - N ~f: r: : • ..-.-.,.:.::"1'-.-. . c:: Dds If) 0.20I- 0.2325:!: 0.0007 i I - - --.-"!" ,I"- " 10-'r • Uuc /1111111111 II U 1 FLWNC W,Z cu seon:h! GIM WNC I Ods 0.151.....1______-" Wt ! ~ Discovery Discovery la-It Q2 (momen tum transferred 60 70 80 90 2000 in the NC process) year - INSERT A-
Fig. 630: History of the search for Flavor Changing Weak Neutral Currrents from the early 1960'8 to the preAen t Fig. 5b: Insel1 A of Fig. Sa.
1I lR \ . _.1
HE RISE OF THE STANDARD MODEL ~ .. ~.. _ .... o- _ ... OF ELEMENTARY PARTICLES . - ...... --\ \ . ~ .. . --\ v"r~' .::::.."'? , ,.- - - ~ -_.-\ '; . ~~ .... - 0... ~ «.; ~ c: 0 UJ , ,(::) > t::)~ . " ...... -.~ \ III ~,.""-J : t::) ~ ~ o= - N ~ ~ .,",; \ u :E Ac.., ~ ~ _..-.- - \ ~~ v"5 -,:, CI/ I U SEARCH FOR FCWNC DECAYS r--T N I c ~I CD ~ C; .-, " ~ o 11 __ 0 -J 0..:: 0 := ~\, - 8 - fLJ.L l (Cornett ) ~~r - · . · _," __ :"V' J «.; - III'" ~ E ... E ~ ,,~ ~ ...... o 0 2 c: 0 10- ~ ~~ ... .c: -o 0...... Q,- ~ U ~------'~ .. ~ ~ >-... u 0 .= ' .'.,' i :'. :.' : . . ' , U - '0 - o , 't! _I ~ j, ,_ ' .• z (UA1) .... -.. - .. .. ' ~~ CI: ..J ~ := 8 -fLP.~'... fL fLl L::---- ~ ~ en «;~ C; ) 'r77777/ ¢~ lI"°e+e - 9 Std. Mode ~ ,,~ 8 r fL'" __.a.. ,////// ." " 10-10 \ ' v 'oJ?11 ",,' \ TrVV ~ «.~ ~ ~ ~ ~ 65 70 75 80 85 90 95 ~ «.4,; yeo r Fi g. 6b: Search (or Flavor Ch&ll~Dg Weak Neutral Current Decays Fig. 7: The rise of the Standard ~ lodel .-49 '20 ..