The 'LASS' Programwhere LASS equals E-135, LASS and SLD

The beginning• In 1975/6 Sharon Traweek and Henry Abarbanel

encouraged me to be in contact with several Japanese groups who might be interested in collaborating on strong interaction spectroscopy studies. This led to a meeting with Ryo Kajikawa, of Nagoya University and the start of a long personal friendship, and of a productive scientific collaboration . Nagoya applied to JSPS for support, and Shiro Suzuki visited SLAC. Thus began the US/

Japan basis for the “LASS” program.

• Prof.Nishikawa pushed the formation of the Japan/US collaboration in HEP, and supported the Nagoya group’s role

on the LASS experiment as part of that activity. Shiro Suzuki

came to SLAC as KEK/Mombusho ACO, and as resident senior leader of the Japanese group.

• SLAC hosted two activities under the early Japan/US program – a series of bubble chamber experiments, and the LASS activity.

• Joe Ballam made the decision – a very wise, generous and impactful one – to hire a series of young Japanese scientists, into short term appointments, using the lab resources offset by the Japan/US investment at SLAC.

• This program had over 30 Japanese visitors working on the experiments through the period 1979 to 1999, with 18 post docs and graduate students working long term at SLAC, in these visiting appointments.

• Around 1990 such temporary positions - a important bridge between

graduate student status and regular employment as faculty or staff on

research - became established in Japan . The SLAC temporary positions

were a very important precedent/exemplar.

• From those times , and from this program , there were 10 graduate students from Japan working at SLAC, from Nagoya University and from Tohoku University , who finished their PhD studies and graduated - and of that group 7 are now working in research at Japanese universities or laboratories.

• There were 15 young Japanese who held these temporary positions at SLAC, and of these 12 now are faculty or staff in Japanese universities or laboratories.

• Nineteen of the young Japanese who worked on this program are

now active in Japanese HEP.

• This is an impressive deliverable from our international, collaborative

activity. I believe it ranks in equal importance to the science that

was carried out.

5

K- p+ Elastic Scattering from K- p K- p+ n at 11 GeV/c

730 k

events

{ NPB 296 (1988) 493 ; Naoki Awaji, Ph.D Thesis, Nagoya (1986) }

6

K- p+ Elastic Scattering: P- wave Amplitude

Amplitude Phase (deg.)

Consistent with elastic unitarity up to ~ 1.05 GeV; BW lineshape description

Clear deviation from BW amplitude and phase behaviour at higher mass

Radial excitation at ~ 1.4 GeV; highly inelastic; elasticity ~ 0.07 (hard to find)

Orbital excitation (q q 3D1 ground state) at ~ 1.7 GeV, elasticity ~ 0.40

Mass = 896.1 MeV

Width = 50.7 MeV

rBW = 3.0 GeV-1

Note : "elasticity" means "branching fraction to K p"

7K- p+ Elastic Scattering : I = ½ S-wave Amplitude

Amplitude Phase (deg.)

Subtract I = 3/2 Amplitude from Total S-wave {Total = | I = 1/2 > + 0.5 | I = 3/2 >}

Result consistent with elastic unitarity up to ~1.5 GeV/c2

Fit with coherent superposition of Effective Range and Resonant amplitudes

( Resonance parameters : M ~ 1.435 GeV/c2, G ~ 0.279 GeV )

Possible radial excitation in 1.9 - 2.0 GeV region, elasticity ~ 0.35

Total

I = 1/2

I = 3/2

The LASS experiment established the full excitation spectrum of both orbital and radial light quark meson states.

Most completely in the strange meson sector, but also in the strangeonium sector.

Examples of direct impact on B physics analysis 12

B0 J/ K+ p- (Marc Verderi et al.){ PRD 71 (2005) 032005 ; BAD 752 }

AFB ~ Re(S* P0)S – P phase in units of p

Mass dependence of S-P phase defines sign of cos(2 ) { Wigner Causality, PR 98 (1955) 145 }

Good agreement with LASS ◊

+ shift of p radians

Clear evidence of K p S-P wave interference effects

~ Re(S* P║)

~ Im(S* P┴)

K+ p- Mass [GeV/c2] K+ p- Mass [GeV/c2]

Analysis of D+ K- p+ e+ ne

Japanese role in the SLD experiment• By this time, the Nagoya group were joined by people from

Tohoku. Prof. Haruo Yuta brought his group to join the Nagoya

activity in the SLAC program, working now on the SLD experiment while still partici- pating in LASS data analysis. The “Ballam plan”, (of lab temporary staff positions), still continued supporting senior resident scientists, and a new set of temporary SLAC scientist appointments.

• The impressive table of those from Japan who played a part in these activities, displays both the past , and the current placement of the

young Japanese scientists. • These Japanese groups helped design and build the CRID

particle identification system, and the important CCD vertex

detector of the SLD detector, run the experiment through its data taking, and participate in the data analysis.

SLD science activities - # Precise measurements of A(b) and A(LR) at the Z mass

# Measurement of alpha-s at the Z mass

# Measurement of R(b) at the Z mass

# Precise measurement of b fragmentation in Z decays

# A test of flavor independence in strong interactions

These were all “TOP CITE” publications (i. e. greater than 50 citations per paper)

Conclusion# strong, productive science program, with ‘hands-on’ learning of designing and building detector instrumentation, running large HEP experiments ‘24/7’, and giving attention to development of the software to support both the data production, and the data analysis of the resulting data.

# the data and the results from LASS provided a broad, empirical foundation on the detailed spectroscopy of light quark meson systems, with particular emphasis on the strange quark.

# the SLD experiment introduced new kinds of detector technology, and with the polarized beams of the high energy collider allowed precision measurements that challenged the SM story for heavy quark couplings.

Conclusions (continued) # development of human resources that are now an

important part of ongoing basic research manpower in Japan. Nineteen professors and staff, now engaged in HEP research within Japan.

# a great number of very good friends from the originating community of Japan/US, some of whom are no longer with us, but who enriched our community, and enabled the creation and sustainability of the program we are celebrating in this symposium. I am thankful for this rich set of very important friends that came into my life only through this Japan/US program.

THE

end

12

B0 J/ K+ p- (Marc Verderi et al.){ PRD 71 (2005) 032005 ; BAD 752 }

AFB ~ Re(S* P0)S – P phase in units of p

Mass dependence of S-P phase defines sign of cos(2 ) { Wigner Causality, PR 98 (1955) 145 }

Good agreement with LASS

+ shift of p radians

Clear evidence of K p S-P wave interference effects

~ Re(S* P║)

~ Im(S* P┴)

K+ p- Mass [GeV/c2] K+ p- Mass [GeV/c2]

US JAPAN PHD THESIS FROM THE SLAC "LASS" PROGRAM

<---------- JAPAN -------------> <----------- US -------------->

DATE NAME INSTITUTION EXPERIMENT NAME INSTITUTION

1986 LASS SINERVO, P S. U.1987 AWAJI, N NAGOYA U LASS1987 FUJII, K NAGOYA U LASS1988 HAYASHI, H NAGOYA U LASS1988 SUGIYAMA, A NAGOYA U LASS1988 LASS BIRD, F S. U.1988 OZAKI, H NAGOYA U LASS1990 LASS BIENZ, T S. U.1993 LASS KWON, Y.J. S. U.1993 LASS RENSING, P S. U.1995 OHNISHI, Y SLD1996 SLD PAVEL, T S. U.1998 OHNISHI, N SLD1999 ABE, K SLD

5 LASS, 3 SLD 5 LASS, 1 SLD

The magnitude, (a), and the phase, (b), of the S-wave and P-wave amplitudes in the mass region below 1.84 GeV/c 2.