Fermilab History and Archives Project

Internal Notes of the E288 Upsilon-Discovery experiment

 

version 1.00, John Yoh, 11/25/05
For more details, see The Experiment Coordinator's Story (pdf format)

Provided below are links to web pages containing many of the internal group documents from the E288 Columbia-Fermilab-Stony Brook experiment at Fermilab -- mostly from the year (6/1976 to 6/1977) leading to the Upsilon discovery. Some of these notes, labelled "Private", "Do Not Make Public", etc. were internal notes when we were on the verge of a discovery, and were afraid of information being leaked to outside before we were ready to announce the discovery. Thus, many of these are of great historical significance, giving insight to the process of a "discovery in progress".

Some other significant notes outside that period are also included, such as important notes and developments prior to the original E70 and E288 proposal, as well as some brief notes and comments on recent consequences of this discovery and the significance of Bottom quark to HEP physics currently.

  • (A) Pre-History and the E288 Proposal-
    1. 1968 -- Lederman et. al. -- Graph from Brookhaven Dimuon experiment -- First Hint of the J/Psi

      Leon's groundbreaking dimuon experiment at Brookhaven National Lab (BNL) saw the first evidence of the J/Psi, subsequently discovered in 1974 by Ting (Di-electron at BNL) and Richter (Mark I Detector at SLAC -- Stanford Linear Accelerator Center). Pity that Leon's mass resolution was not better, and that his data was published before the GIM model predicted charm (J/Psi is the charmonium -- made up of a charm quark and a charm anti-quark) -- we show here a plot of the dimuon mass distribution, with a broad peak near 3 GeV.

    2. June 17, 1970 -- Proposal for E70 -- Leptons, di-leptons -- submitted to Fermilab and approved.

      The early phases of this progression of experiments concentrated on the study of single electrons produced at large angles from proton-nucleus collisions, and coincide with the commissioning of the Fermilab Main Ring accelerator, which accelerated protons up to an energy of 200 Gev, subsequently upgraded to 400 GeV.

    3. February, 1974 -- Proposal E288 (formerly E70 phase 3) -- updated proposal for Di-electrons and Di-muons

      The Fermilab PAC (Program Advisory committee, which recommended which experiments to approve) asked Leon to define in more detail the di-lepton phase of the E70 experiment, and subsequently issued a new experiment number E288 to that phase.

    4. April 26-27, 1974 -- Shelly Glashow's (of GIM -- i.e., charm hypothesis fame, later winner of 1979 Nobel Prize in Physics) "prediction" at the 4th International Conference on Experimental Meson Spectroscopy on 3 scenarios of charm discoveries to come -- he doesn't have to eat his hat since the charmonium (aka subsequently J/Psi) were discovered with 6 months by "outlanders", that is, those people who did not work on Hadron spectroscopy, the subject of this particular conference.!!!!

    5. August, 1974 -- Three months before "the November Revolution" (J/Psi discovery) -- front page of theory preprint by Gaillard, Lee (both at Fermilab), and Rosner (Minnesota)
      Gaillard, Lee and Rosner paper, which predicted the J/Psi discovery, laid out the charm system in great detail. In fact, Mary K. Gaillard told Leon and me (JKY) over lunch at Fermilab in August, 1974 that Leon's BNL bump is the charmonium.

      Leon responded that he had been looking for that, with an experiment at CERN ISR looking at di-electrons from 1970 onwards (J/Psi signal swamped by unexpected high Pt photons from Pi-zero decays as well as poor calibration problems) as well as the experiments which has already started at Fermilab --E70, E288, etc. Looking at Single e, muon, di-e, and di-muon. He was too slow--the J/Psi was discovered while E70 was still investigating single e's.

    6. November, 1974 "The November Revolution" -- discovery of the J/Psi at BNL, SLAC--eventually determined to be the charmonium (made up of a pair of charm and anti-charm quarks). Later D (charmed mesons) were also discovered at SLAC

  • (B) E288 -- early phases at Fermilab -- 1975-1976 -- ee1 (di-electrons phase 1), uu1 (Di-Muons phase 1)
    1. Schemetic of the 3 phases of E288 -- ee1, mumu1, and mumu2

    2. January, 1976 -- High Mass Di-electrons and Oopsleon (6.0)

      Why did we brashly name the 6.0 particle Upsilon (though in the PRL paper, we soften this name to describe either the 6.0, if confirmed, or the entire high mass di-lepton region)? Here are some thoughts --
      (1) Jeff Weiss researched the Greek alphabet, and found 4 possibilities --we didn't like iota. Upsilon sounded promising. Furthermore, Walter Innes (I think) pointed out that if the particle is not confirmed, we could call it OOpsLeon. Due to our heritage (our Spokesman is well known for bad puns), we could not resist.
      (2) There were at least 2 additional events which barely failed our cuts. If these were included, the significance would be at least 1/2 sigma higher -- but, like most HEP physicists, we are sufficiently honest that we never thought of tuning our cuts to generate a better looking signal.
      (3) Our experiment only looked at one mass plot, unlike others that looks at hundreds of plots; so, a 2-1/2+ sigma effect was` significant for us -- while other experiments would expect to see many such statistical fluctuations in their hundreds of plots.

  • (C) First Hint of the real Upsilon (9.5) -- November 1976

     

    1. November 17, 1976 -- JKY -- "Bigger Upsilon" -- First hint of Upsilon (9.5)

      November 17, 1976, about 7-1/2 Months before the Upsilon discovery, E288 had a first hint of the Upsilon (9.5). John Yoh (JKY), experiment coordinator, was responsible, among other things, for taking the data tapes to the computing center, performing the first stage data reduction, and verifying that the data was good ("Bicycle On-line") -- which included a first look at the dilepton mass distribution. On that date, he wrote an internal note ("***DO NOT MAKE PUBLIC***") "From the people who brought you the Upsilon (6.0), a bigger (but not necessary better) resonance.

      The note discribed a cluster of 10 events within a 300 MeV wide window, where one would expect (based on adjacent bins) 1.75 events. The significance is stronger than the original Upsilon (6.0), which was not confirmed and was determined to be a statistical fluctuation. The 9.5 significance is roughly 1 in 160, vs. 1 in 50 for the 6.0.

      Fortunately, we did not have to decide then whether to announce yet another new resonance, since we knew that our forthcoming Mumu2 phase (due to start in March 1977), with 100 times higher sensitivity per day, would settle the veracity of the 9.5 within weeks (well, it actually took 2 months due to the fire that disrupted data-taking for 1+ weeks).

      Nevertheless, John Yoh, put a bottle of French Champagne (Mumm's ??) in the trailer control room refrigerator, with 9.5 written on it -- to be opened when discovery is confirmed).

    2. Comments on the "Bigger Resonance" by Walter Innes and Bob McCarthy/Bud Good Walter Innes claimed that the significance was 6 times higher. Bob and Bud claimed that the dimuon mass peak was too narrow.

    3. November 21, 1976 JKY -- Response to the 9.5 hint -- comments

      John Yoh replied to Bob/Bud that some of the events nearby could be part of the resonance, thus broadening the peak.

  • (D) MuMu2 -- preparation, installation, studies

    The E288 MuMu2 experiment, which discovered the Upsilon, the particle made up of a Bottom and an Anti-bottom quark, is a collaboration of CFS (Columbia University, with Leon Lederman as Spokesman and John Yoh as Experiment coordinator, Fermilab --with Taiji Tamanouchi, senior member, and Stony Brook, with Bud Good senior member). The CF group which originated the experiment (from the early 1970's E70 stages), were joined by the Stony Brook (SUNY--State University of New York at Stony Brook) group in 1976 for the E494 di-hadron phases and subsequently the MuMu2 phase.

    The members of the experiment at the time of the Upsilon discovery include (see some examples of many of their contributions to the preparation of the MuMu2 detector below -- note that many more notes exist but we don't have room for all of them)

    Columbia :
    LML (Leon Lederman, Spokesman and originator of the experiment),
    JKY (John Yoh, experimental coordinator 1975-1977, data reduction expert)
    SWH (Steve Herb, upgrade manager -- reconfiguration of the target box, absorber)
    DH (David Hom)
    JCS (Johannes C "Hans" Sens)
    HDS (H. David Snyder)

    Fermilab :
    TY (Taiji Yamanouchi, senior member)
    JAA (Jeff Appel, experimental coordinator 1973-1975 while working for Columbia)
    BCB (Bruce C Brown -- detector expert -- construction of new wire chambers)
    CNB (Chuck Brown)
    WRI (Walter Innes, reconstruction software)
    KU (Koji Ueno, Monte Carlo expert)

    Stony Brook :
    ASI (Al Ito)
    HJ (Hans Jostlein)
    DMK (Dan Kaplan, graduate student -- whose wrote his thesis later on the Upsilon discovery results -- he is also responsible for online computing)
    RDK (Bob Kephart)

    Previous members who left prior to the discovery:
    David Saxon
    Jean-Paul Repellin
    Maurice Bourquin
    Jeff Weiss

    Engineers and Technician who played strong roles in the preparation of our detector:
    Bill Sippach (electronics)
    Karen Kephart, Ken Grey, Frank Piersall, Jack Upton
    Many others, too many to name
    Members of Fermilab accelerator division, Proton division, etc.

     

    1. A schematic of the E288 MuMu2 detector -- note that the absorber is placed just downstream of the target, thus allowing us to increase the intensity of the incoming beam and have a higher interaction rate. Furthermore, the initial absorber is Be (Beryllium), which, haveing a very low Z, give the minimum multiple scattering to the outgoing muons, and thus preserves a good angle resolution.
    2. February 12, 1975 -- LML (Leon Lederman) memo on Dimuons -- MuMu2 phase
    3. January 28, 1976 -- LML, TY (Taiju, Yamanouchi), others -- Super 288 white paper
    4. February 17, 1976 -- JKY (John Yoh) expected E288 MuMu2 Signal and Background; Options for improving E288 MuMu2 signal/background.
    5. May 10, 1976 -- BCB (Bruce Brown) Muon Momentum confirmation with a steel magnet
    6. June 22, 1976 -- Leon Lederman, Walter Innes, Steve Herb -- Propose PWC (Proportional Wire Chambers) system for MuMu2 (later built by Bruce Brown)
    7. June 28, 1976 -- LML (MuMu2 status report)
    8. July 3, 1976 -- Herb -- MuMu2 MWPC Proposal
    9. July 30, 1976 -- LML Target Box MuMu2 E288
    10. August 23, 1976 -- JKY (Yoh), CNB (Chuck Brown), SWH (Herb) -- MuMu2 hodoscope and triggering
    11. September 23, 1976 -- DMK (Daniel Kaplan) What everyone should know about our computer (online data-acquisition system)
    12. September 30, 1976 -- SWH (Herb) Sketch of the MuMu2 Target box design
    13. ??? LML, HS (Hans Sens) -- DDC Proposed Read-Out system
    14. February 27, 1977 (ASI (Al Ito), SWH (Herb) -- MuMu3 Collim(ator) Modification
    15. February 28, 1977 JKY (Yoh) -- A and B2 Level compression status (Data reduction)
    16. February 19, 1977 WRI (Innes) MuPC (Software status)
    17. April 25, 1977 JKY (Yoh) -- E288 Jobs during Shutdown (after test run)
    18. ??? JKY (Yoh) E288 Physicists in Charge
    19. May 12, 1977 -- SWH (Herb) Survey summary
    20. May 17, 1977 JKY (Yoh) -- MuMu2 Offline Jobs
    21. May 18, 1977 JKY (Yoh) Study of A level Compression/Y PWC Eff(iciency)
    22. May 29, 1977 HJ (Hans Jostlein) The Field of the MuMu2 Iron Magnet
    23. June 1, 1977 WRI (Innes) MuPCPL status update (software)
    24. June 3, 1977 WRI (Innes) Estimated efficiency of the Directional Drift Chamber
    25. June 8, 1977 JKY (Yoh) Compressed Data files
    26. June 1977 JKY (Yoh) One of the many sheets of data on the information of each run
    27. June 7, 1977 Willy Yang, S. Baker -- SEM calibration (needed for knowing the number of collisions)
    28. June 13, 1977 JCS (Sens) New MC acceptance for 1500A
    29. June 20, 1977 DMK (Kaplan) Magnetic field study
    30. June '77 ?? RDK (Kephart) Keeping JKY honest + comment on resolution
    31. June 1977 ?? JKY (Yoh) Future Options for E288 -- Immediate apparatus options
    32. Note : Many other notes exist, these are just a few leading to the Upsilon discovery, showing some of the effort put in by many people -- all of us contributed much more than can be described in only a few notes,
  • (E) The Upsilon Discovery -- June 1977 and just before
    1. April 1977 -- Test run prelim result

      This undated plot (probably March-April 1977) shows the older ee1/mumu1 results (on top) compared with the test run results at the bottom -- there is some evidence of excess events near 9.5 in the short 1-week test run (152-163) -- though the evidence is not yet compelling.

    2. June 6, 1977 "Data Status and Running Conditions" -- JKY (Yoh)

      The results of data collected in the periods May 14-5 and May 28 -- June 4 (the one week downtime was due to the fire in the detector hall) indicated a 9.5 bump of at least 8 sigma significance. We start to get a "to-do" list to verify this bump -- making sure that this is not due to some artifact such as detector problems, etc.

    3. June 17, 1977 "Studies on Systematic problems and Backgrounds" -- JKY (Yoh)

      Efforts were being made to study this resonance, which had by that time reached 10+ sigma statistical significance. So, we were mainly concerned now with whether some experimental defects (artifacts) could cause such a peak. Many studies are detailed in this note -- as well as other notes.

    4. June 20, 1977 JKY (Yoh) "Mu Mu II results : Part 1"

      Some more studies, on the way to a publication and discovery announcement.

    5. 6/30/77 Steve Herb announced the Upsilon (9.5) discovery in a seminar at Fermilab

    6. July 1, 1977 "Observation of a Dimuon Reosnance at 9.5 GeV in 400 Gev Proton-Nucleus collisions" was submitted to PRL (Physical Review Letters) and was published in the 1 Aug 1977 issue of PRL

    7. August 1977 Leon announce the discovery of the Upsilon at the 1977 summer conferences, at the EPS conference in Budapest, and the Lepton-Photon conference at Hamburg.

  • (F) Afterwards -- How the study of Bottom quark become more than 1/3 of current HEP endeavors

     

    1. Confirmation of the Upsilon and Upsilon' by DESY -- October 1977 -- The Upsilon and Upsilon' particles were quickly confirmed by the DESY DORIS e+e- storage ring; they reconfigured the ring, adding more RF cavities to raise the energy up to 5.1 GeV (Mass of 10.2 Gev) -- previously, they were limited to about 8.5 GeV. The similar ring SPEAR, at SLAC, was not able to go that high.
    2. 1979 -- Discovery of the Upsilon 4S and 5S states at CESR (CLEO, CUSB) -- At the time of the Upsilon discovery, the Cornell CESR storage ring was under construction, along with the large magnetic detector CLEO. After the discovery, Yoh, Herb and Lederman proposed the CUSB experiment (subsequently joined by Franzini's and Finocchiaro's group) -- and both CLEO and CUSB co-discovered the Upsilon 4S and 5S states. Those 2 states are above the threshold for decaying into a pair of B mesons, and thus have much smaller branching ratios into dielectrons or dimuons -- making them not observable at Fermilab by E288.
    3. 1980 -- Observation of electrons from Upsilon(4S) decays, first evidence of B mesons (CUSB) -- The CUSB experiment saw the first indirect evidence for the B meson by observing electrons in the decay in the Upsilon(4S) state, where none were seen in adjacent regions -- furthermore, the electrons had an energy distribution which strongly indicated that the B meson decayed to a heavy Object + electrons, etc. consistant with the hypothesis that almost all B meson would decay to a D (charm meson with mass of about 2 GeV) + others, which is what one would expect if the B meson is formed from a fifth bottom quark.
    4. 1980 -- Observation of B meson by CLEO -- CLEO discovered the B meson in its decays into a D meson + pions. They observed a mass peak.
    5. 1994-5 -- Observation of the Top quark, in its decays into B meson and W -- at Fermilab (CDF, DZero)- Many subsequent physics experiments used the B meson as a tool for new physics -- mostly due to the fact that the B meson has a sufficiently long lifetime that it will travel a short distance before its decay -- of order minimeters -- these "secondary" vertices can be distinguished and provide a good signature that allow one to isolate a b signal from the much more copious light-quark jets. For example, The CDF collaboration saw the Top signal in 1994-5 using the fact that a Top particle would decay into a W + a B meson -- with the B meson giving a secondary vertex..
    6. 1990's -- B factory (BaBar at SLAC and Belle at KEK) -- A large fraction of Particle physics effort currently is on B meson studies. Roughly 1/5 of the experimental HEP experimental physicists are currently working on 3 B factories -- BaBar at SLAC (USA), Belle at KEK (Japan), and CLEO at Cornell (USA). In addition, roughly 1/3 of the HEP physicists working in the hadron colliders (CDF and DZero at Fermilab, USA now, and ATLAS, CMS, LHB at the forthcoming LHC collider (CERN, Europe) will be working on B meson studies and/or using B as a tool to search for new physics (such as the Higgs -- for a range of masses below 130 GeV or so, the Higgs is expected to mostly decay into a pair of B mesons).

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