� Precision Beauty at High Sensitivity Chris Quigg Fermilab Nikhef · Amsterdam · October 29, 2019 See also “Dream Machines” 1808.06036 “Perspectives and Questions” zenodo.3376597
Origin Story . . . PHYSICAL REVIEW LETTERS VOLUME )9, NUMBER 20 14 NovEMBER 1977 400-GeV pN → µ + µ − + X TABLE II. Sensitivity of resonance parameters to 04- continuum slope. Continuum subtraction of Eq. (1) but b varied by + 2(T. Errors are statistical with only. b = 0. 977 GeV 5 = 0. 929 GeV O c 0. 2 9. 40 + 0. 013 9. 40 + 0. 014 Y M( (GeV) 0. 17 + 0. 01 Bdo/dy(„-& 0. 18 + 0. 01 (pb} ~ o. o t ~, (Gev) 10. 00 ~ 0. 04 10. 01 ~ 0. 04 bI blab B do/dy 0. 068 + 0. 007 0. 061 + 0. 007 -g (pb) I 10. 43 + 0. 12 10. 38 + 0. 16 ~3 (GeV) 0. 008 + 0. 007 B do/dy 0. 014 + 0. 006 / ~ -o (pb) 9 l0 14. 1/16 15. 4/16 per degree of mass (GeV} freedom FIG. 2. Excess of the data over the continuum fit of Eq. (1). Errors shown are statistical only. The solid M (Υ ′ ) − M (Υ) M ( υ ′′ ) − M (Υ ′ ) E288 curve is the three-peak fit; the dashed curve is the two-peak fit. Two-level fit 650 ± 30 MeV ty and. also the estimated uncertainty due to mod- Three-level fit 610 ± 40 MeV 1000 ± 120 MeV el dependence of the acceptance calculation. ) (iii) There is evidence for a third peak Y "(10. cise form of the continuum. The first test is to 4) M ( ψ ′ ) − M ( J / ψ ) ≈ 590 MeV b, in Eq. (1). Varia- this is by no means established. vary the slope parameter, although tion each way by 20 yields the results Examination of the Pr and decay-angle given in distribu- General motivation: J / ψ , τ discoveries Table II. A detailed study has been made of the tions of these peaks fails to show any gross dif- error matrix representing correlated uncertain- ference from adjoining continuum mass bins. Kobayashi–Maskawa CPV insight ties in the multiparameter fit. The correlations An interesting is the ratio of (Bda/ quantity dy)l, , for Y(9. 4) to the continuum increase the uncertainties of Tables I and II by cross section Chris Quigg Beauty, etc. Nikhef · 29.10.2019 1 / 46 , at M = 9. 40 GeV: This is 1. 11 &15%. (d'o/dmdy)I, in the results presented ~ 0. 06 GeV. Further uncertainties above arise from the fact that the continnum fit Table III presents and cross mass splittings is dominated by the data below 9 GeV. Nature sections systematic errors) under (including the from Eq. (1) two- and three-peak could provide reasonable departures hypotheses and compares above this mass. These issues must wait for a them with theoretical predictions to be discussed large increase especial- in the number of events, below. ly above -11 GeV. the primary conclu- There is a growing literature which relates However, the sions are independent of these uncertainties Y to the bound state of a new quark (q). ' " Eichten (q) and its an and may be summarized as follows: (i) The structure and Gottfried' have cal- antiquark at least two narrow peaks: Y(9. 4) and contains culated the energy spacing to be expected from Y'(10. 0). (ii) The cross section for Y(9. 4), (Bda/ dy) i, „ is' 0. 18+ 0. 07 pb/nucleon. the potential model used in their accounting for (The error in- the energy levels in charmonium. Their potential cludes our + 25/o absolute normalization uncertain- V(r) = — ~4m, (m, )/r +r/a' (2) predicts line spacings and leptonic widths. The TABLE I. Resonance fit parameters. Continuum level spacings t Table III(a)] suggest that the shape is given by Eq. (1). Errors are statistical subtraction of the potential may be oversimplified; we note only. that M(Y') -M(Y) is remarkably close to M (g') -M(4)" 2 peak 3 peak of Bda/dyl, -, Table III(b) summarizes estimates 9. 41 + 0. 013 for qq states and ratios of then=2, 3 states to 9. 40 + 0. 013 Y m, (GeV) 0. 18+ 0. 01 0. 18 + 0. 01 the ground state. Cascade models Bda/dye o (pb) (Y produced 06 + 0. 03 10. 10. 01+ 0. 04 Y m, (GeV) as the radiative decay of a heavier P state formed Bdo. /dye~ 0. 069 + 0. 006 0. 065+ 0. 007 0 (pb) and direct production by gluon amalgamation) 40 + 0. 12 10. M3 (GeV) Q = — & to Q =-', . We processes seem to prefer B do/dyj, 0. 011+ 0. 007 , (pb) that the ratios in Table III may re- note finally 19. y2 per degree of 9/18 14. 2/16 quire modification due to the discrepancy between freedom the observed and the universally spacing used 1241
Volume 66B, number 3 PHYSICS LETTERS 31 January 1977 HEAVY QUARKS IN e÷e - ANNIHILATION* E. EICHTEN and K. GOTTFRIED Laboratory of Nuclear Studies, Cornell University, Ithaca, New York, 14853, USA Received 16 November 1976 There are many speculations that there exist quarks Q considerably heavier than the charmed quark. Their QQ states will display a far richer spectrum of monochromatic photon and hadron transitions than charmonium. The most important features of this spectrum - in particular, its dependence on the mass of Q - are outlined. Eichten & Gottfried: CESR Proposal (November 1976) The literature bristles [ 1 ] with conjectured quarks I000 [~((iDick~75:(:i;L4'7.4:.::;~":':'~:~::";::::'::;;'~";#'~-;;~~:' considerably heavier than the charmed quark. We do not want to pass judgement on the plausibility of these speculations here. Our principal purpose is to point out a quite obvious fact: if such super-heavy quarks Q ac- tually exist and have masses mQ below 15 GeV, the new generation of e+e - storage rings will find a spec- trum of Q(~ bound states and resonances that is far W richer than the cc spectrum in the 3-5 GeV region. _g,~ _ This is so because for mQ ~> 3.5 GeV we expect three 351 bound states below the threshold for the Zweig- allowed decays of QQ. As a consequence, the QQ E (2 S ) − E (1 S ) ≈ 420 MeV ~oo spectrum will display a very intricate and complex m~ array of photon and hadron transitions. In addition, the region above the Zweig-decay threshold will con- 0 i I I I tain a rich assortment of rather narrow resonances. 6 2 3 4 5 Planning for experiments at CESR, PEP and PETRA O (GeV) FFi might bear this enticing possibility in mind. � General: # of narrow 3 S 1 levels ∝ M Q That an increase of quark mass leads to stronger Fig. 1. QQ excitation energies as a function of quark mass. The energies shown are found from the Schr6dinger equation binding of Q(~ states is obvious without any theory. with (1) as potential. All relativistic corrections to the excita- Thus sg just fails to have a bound 1 - state, whereas Chris Quigg Beauty, etc. Nikhef · 29.10.2019 2 / 46 tion spectrum are ignored. The onset of the Q~+ Qq conti- cg has two. Hence we expect further QQ 1- states nuum is also shown. Its position relative to the QQ spectrum can be bound by a sufficiently large increase of mQ, does depend on various corrections; see the discussion related and it only remains to quantify "sufficiently". The to eqs. (2) and (3). success of the charmonium model [2-4] allows one The length a is assumed to be a universal constant cha- to compute the mQ-dependence of the QQ spectrum racterizing the quark confinement interaction. The with a considerable degree of confidence, and thereby to estimate the value ofmQ where a third 3S state is Coulombic interaction has a strength %(m~) whose mQ dependence is given by the well-known renormali- bound. As in charmonium, we [4] use a static QQ interac- zation group formula from color gauge theory. From tion our analysis [51 of the c~ system, we have a = 2.22 GeV -1 and as(m 2) = 0.19. v(r) = ! + r The QQ excitation spectrum predicted by V(r) is Sr a2. (1) shown in fig. 1 as a function of mQ. (Fine structure * Supported in part by the National Science Foundation. effects - not yet understood in charmonium - are 286
Why choose M Q = 5 GeV? ν µ N → µ + + anything Excess events at high inelasticity observed in ¯ ν q ) / dy ∝ (1 − y ) 2 V − A : d σ ( ν q ) / dy ∝ 1 d σ (¯ “high- y anomaly” could be explained by � u � with m b ≈ 4 – 5 GeV b R Also at Budapest 1977. . . CDHS experiment ruled out the high- y anomaly Chris Quigg Beauty, etc. Nikhef · 29.10.2019 3 / 46
Υ(1 S ) , Υ(2 S ) leptonic widths ❀ Q b = − 1 3 (DORIS, 1978) Chris Quigg Beauty, etc. Nikhef · 29.10.2019 4 / 46
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