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Home , Chris Quigg, Tevatron

The ’s Impact on · 2 Hundreds of articles

Tevatron Ph.D.s 461 fixed-target 18 small- 965 CDF & D0

3 Two New Laws of Nature +

R 3 R 2 eR 1 bR tR sR cR 3 dR 2 uR 1 L L eL

tL cL uL bL sL dL

Symmetries dictate strong, weak, electromagnetic interactions

4 CDF & D0 Highlights

Top quark discovery· Higgs-boson search Exacting measurements: mt, MW, Bs oscillations Heavy-flavor physics Search for new particles and forces Testing elements of the “”

Scientific interests and capabilities expand and deepen respond to new opportunities deliver a harvest of results not imagined at the start

5 Strong Interactions:

Conundrum: are made of quarks that seem independent, but quarks can’t be liberated.

6 Evolution of the strong coupling

7 Quantum Chromodynamics

8 REPORTS mud,correspondingtoMp ≅ 135 MeV,are difficult. vector meson (r, K*) octets that do not require (25, 26)andforoursetup(27)], simulating di- They need computationally intensive calculations, the calculation of disconnected propagators. rectly at physical mud in large enough volumes, with Mp reaching down to 200 MeV or less. Typical effective masses are shown in Fig. 1. which would be an obvious choice, is still ex- 5) Controlled extrapolations to the contin- 3) Shifts in hadron masses due to the finite tremely challenging numerically. Thus, the stan- uum limit, requiring that the calculations be size of the lattice are systematic effects. There dard strategy consists of performing calculations performed at no less than three values of the are two different effects, and we took both of at a number of larger mud and extrapolating the lattice spacing, in order to guarantee that the them into account. The first type of volume de- results to the physical point. To that end, we use scaling region is reached. pendence is related to virtual pion exchange be- chiral perturbation theory and/or a Taylor expan- Our analysis includes all five ingredients tween the different copies of our periodic system, sion around any of our mass points (19). listed above, thus providing a calculation of the and it decreases exponentially with Mp L.Using 5) Our three-flavor scaling study (27)showed light hadron spectrum with fully controlled sys- MpL > 4 results in masses which coincide, for that hadron masses deviate from their continuum tematics as follows. all practical purposes, with the infinite volume values by less than approximately 1% for lattice 1) Owing to the key statement from renor- results [see results, for example, for pions (22) spacings up to a ≈ 0.125 fm. Because the sta- malization group theory that higher-dimension, and fore baryons (23, 24)]. Nevertheless, for one tistical errors of the hadron masses calculated in local operators in the action are irrelevant in the of our simulation points, we used several vol- the present paper are similar in size, we do not continuum limit, there is, in principle, an un- umes and determined the volume dependence, expect significant scaling violations here. This is limited freedom in choosing a lattice action. which was included as a (negligible) correction at confirmed by Fig. 2. Nevertheless, we quantified There is no consensus regarding which action all points (19). The second type of volume de- and removed possible discretization errors by a would offer the most cost-effective approach to pendence exists only for resonances. The cou- combined analysis using results obtained at three the continuum limit and to physical mud.Weuse pling between the resonance state and its decay lattice spacings (19). an action that improves both the gauge and products leads to a nontrivial-level structure in We performed two separate analyses, setting fermionic sectors and heavily suppresses non- finite volume. Based on (20, 21), we calculated the scale with MX and MW.Theresultsofthese physical, ultraviolet modes (19). We perform a the corrections necessary to reconstruct the reso- two sets are summarized in Table 1. The X set is series of 2 + 1 flavor calculations; that is, we nance masses from the finite volume ground- shown in Fig. 3. With both scale-setting proce- include degenerate u and d sea quarks and an state energy and included them in the analysis dures, we find that the masses agree with the additional s sea quark. We fix ms to its approxi- (19). hadron spectrum observed in nature (28). mate physical value. To interpolate to the phys- 4) Though important algorithmic develop- Thus, our study strongly suggests that QCD ical value, four of our simulations were repeated ments have taken place recently [for example is the theory of the , at low on November 29, 2008 with a slightly different ms.Wevarymud in a range that extends down to Mp ≈ 190 MeV. Table 1. Spectrum results in giga– volts. The statistical (SEM) and systematic uncertainties 2) QCD does not predict hadron masses in on the last digits are given in the first and second set of parentheses, respectively. Experimental physical units: Only dimensionless combinations masses are isospin-averaged (19). For each of the isospin multiplets considered, this average is (such as mass ratios) can be calculated. To set the within at most 3.5 MeV of the masses of all of its members. As expected, the octet masses are more overall physical scale, any dimensionful observ- accurate than the decuplet masses, and the larger the strange content, the more precise is the able can be used. However, practical issues in- result. As a consequence, the D mass determination is the least precise. fluence this choice. First of all, it should be a quantity that can be calculated precisely and X Experimental (28) MX (X set) MX (W set) www.sciencemag.org whose experimental value is well known. Sec- r 0.775 0.775 (29) (13) 0.778 (30) (33) ond, it should have a weak dependence on mud, K* 0.894 0.906 (14) (4) 0.907 (15) (8) so that its chiral behavior does not interfere with N 0.939 0.936 (25) (22) 0.953 (29) (19) that of other observables. Because we are con- L 1.116 1.114 (15) (5) 1.103 (23) (10) sidering spectral quantities here, these two con- S 1.191 1.169 (18) (15) 1.157 (25) (15) ditions should guide our choice of the particle X 1.318 1.318 1.317 (16) (13) whose mass will set the scale. Furthermore, the D 1.232 1.248 (97) (61) 1.234 (82) (81) particle should not decay under the strong in- S* 1.385 1.427 (46) (35) 1.404 (38) (27) Downloaded from teraction. On the one hand, the larger the strange X* 1.533 1.565 (26) (15) 1.561 (15) (15) content of the particle, the more precise the mass W 1.672 1.676 (20) (15) 1.672 determination and the weaker the dependence on Light hadron spectrum with dynamical mud.ThesefactssupporttheuseoftheW baryon, the particle with the highest strange content. On Fig. 3. The light hadron the other hand, the determination of baryon dec- spectrum of QCD. Hori- 2 uplet masses is usually less precise than those of zontal lines and bands are m = E0/c the octet. This observation would suggest that the experimental values the X baryon is appropriate. Because both the with their decay widths. W and X baryon are reasonable choices, we Our results are shown by carry out two analyses, one with MW (the W set) solid circles. Vertical error and one with MX (the X set). We find that for all bars represent our com- three gauge couplings, 6/g2 =3.3,3.57,and3.7, bined statistical (SEM) and both quantities give consistent results, namely systematic error estimates. a ≈ 0.125, 0.085, and 0.065 fm, respectively. To p, K,andX have no error fix the bare quark masses, we use the mass ratio bars, because they are pairs M /M ,M /M or M /M ,M /M .We used to set the light quark p W K W p X K X mass, the strange quark determine the masses of the baryon octet (N, S, mass and the overall L, X)anddecuplet(D, S*, X*, W)andthose scale, respectively. members of the light pseudoscalar (p, K)and BMW

1226 21 NOVEMBER 2008 VOL 322 SCIENCE www.sciencemag.org 9 Heavy flavors

Production and decay of quarkonium states Measurements of b- and t-quark production

Bc mass and lifetime Masses and lifetimes of B mesons and baryons Unique source of information on many B-baryons

Orbitally excited B and Bs mesons X(3872) mass and quantum numbers Important evidence on D0 mixing Precise CP for D0 → π+π–, B+ → J/ψK+ High-sensitivity searches for rare dimuon decays

10 Frequency of Bs oscillations

-1 CDF Run II Preliminary L-1 = 1.0 fb 2 CDF Run II Preliminary L = 1.0 fb data 2± 1 95% CL limit 17.2 ps-1 1.5 1.645 sensitivity 31.3 ps-1 1 data ± 1.645 Amplitude data 1± 1.645 (stat. only) 0.5 0 0 -0.5

-1 -1 Fitted Amplitude -1.5 data -2 -2 cosine with A=1.28 0 5 10 15 20 25 30 35 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 -1 ms [ps ] Decay Time Modulo 2/ms [ps]

–1 Δms = 17.77 ± 0.13 ps 11 D0 top-quark specimen

......

12 CDF top-quark specimen

13 Electroweak theory joins electromagnetism and weak interactions (radioactivity)

14 Top mass in the electroweak theory

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120 Top Mass (GeV)

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15 Top mass in the electroweak theory

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120 Top Top Mass (GeV)

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15 MassTop-quark of the Top mass Quark 15 July 2011 (* preliminary)

CDF-I dilepton 167.4 ±11.4 (±10.3 ± 4.9)

DØ-I dilepton 168.4 ±12.8 (±12.3 ± 3.6)

CDF-II dilepton 170.6 ± 3.8 (± 2.2 ± 3.1)

DØ-II dilepton 174.0 ± 3.1 (± 1.8 ± 2.5)

CDF-I lepton+jets 176.1 ± 7.4 (± 5.1 ± 5.3)

DØ-I lepton+jets 180.1 ± 5.3 (± 3.9 ± 3.6)

CDF-II lepton+jets 173.0 ± 1.2 (± 0.6 ± 1.1)

DØ-II lepton+jets 174.9 ± 1.5 (± 0.8 ± 1.2)

CDF-I alljets 186.0 ±11.5 (±10.0 ± 5.7)

CDF-II alljets * 172.5 ± 2.1 (± 1.4 ± 1.5)

CDF-II track 166.9 ± 9.5 (± 9.0 ± 2.9)

CDF-II MET+Jets * 172.3 ± 2.6 (± 1.8 ± 1.8)

Tevatron combination * 173.2 ± 0.9 (± 0.6 ± 0.8) (± stat ± syst) 2 CDF March’07 12.4/dof ± = 2.7 8.3/11(± (68.5%)1.5 ± 2.2) 0 150 160 170 180 190 200 m (GeV/c2) top 16 MassW of the mass W Boson Measurement MW [MeV] CDF-0/I 80432 ± 79 D∅-I 80478 ± 83

D∅-II (1.0 fb-1) 80402 ± 43

CDF-II (2.2 fb-1) 80387 ± 19

D∅-II (4.3 fb-1) 80369 ± 26 Tevatron Run-0/I/II 80387 ± 16 LEP-2 80376 ± 33 World Average 80385 ± 15

80200 80400 80600

M [MeV] March 2012 W 17 Missing link: the agent that Differentiates weak, EM interactions Gives masses to the weak force particles Sets masses & family patterns of quarks & leptons

Textbook hypothesis:

18 , W, and the Higgs boson

A. Kotwal 19 Higgs-boson search 20 Higgs-boson search 20 Diverse searches for new phenomena Limits on supersymmetric particles extra spatial dimensions signs of new strong dynamics new gauge bosons magnetic monopoles … Tevatron experiments did not find what is not there (A few observations do not match expectations) 21 Puzzle #1: Expect New Physics on TeV scale, but no sign of flavor-changing neutral currents.

Great interest in searches for forbidden or suppressed processes

Puzzle #2: Expect New Physics on TeV scale, but no quantitative failures of EW theory

22 The unreasonable effectiveness of the standard model

23 Thanks to the dreamers and builders!

Thanks to Tevatron experimenters!

Thanks to all who made the Tevatron run so beautifully!

Thanks to our patrons!

Continued success to the LHC!

Onward to Fermilab’s next great instrument! 24 Continued success to the LHC! Early Tevatron history: H. Edwards, Ann. Rev. Nucl. Part. Sci. 35, 605 (1985).

Recent overview: S. Holmes, R. S. Moore, and V. Shiltsev, JINST 6, T08001 (2011).

CERN Courier: CQ, “Long Live the Tevatron,” R. Dixon, “Farewell to the Tevatron”

Anecdotal accounts: V. Shiltsev, “Accelerator Breakthroughs, Achievements and Lessons from the Tevatron Collider,” 2010 John Adams Lecture; J. Peoples, Wilson Prize Lecture, “The Tevatron Collider: A Thirty Year Campaign” S. Holmes, DPF 2011 Lecture, “Celebrating the Tevatron: the Machine(s)”

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