Progress and Proposal: Task A by Usha Mallik

1
Progress and Proposal Task AbyUsha Mallik

• for
• Prafulla Behera1, Xuedong Chai3, Mat Charles1,
  Alex Schreiner2, Saravanan Veerasami3, Veronique
  Ziegler3 (and Mark Kane4)
• Past Wolfgang Mader (at TSU, Dresden)
• Niels Meyer (at Hamburg University, DESY)
• Ajit Mohapatra (at U. Wisconsin)
• Gerald Grenier (at U. of Lyon)
• 1 Assistant research Scientist 2 Postdoc 3
  Graduate Student
• 4 Undergraduate Student

2
Programs I

• BABAR
• 390 fb-1 data collected
• Analysis done with 230 fb-1 (Mat Charm AWG
  co-covenor)
• Charm baryon production
• from continuum and from B-decays
• charm baryon pair production from B-decays
• Baryon spin determination
• Excited charm baryon states and spin
  determination
• (Addition CP violation)

3
Programs II

• International Linear Collider
• Particle Flow Algorithm (PFA)
• Never been accomplished before
• More complex than originally envisaged
• Integral part of detector specification at ILC
  (driven by Physics needs)

4
New Program

• ATLAS at LHC
• Motivation Excellent Physics Potential
• SLAC joined ATLAS collaboration in summer 06
• A Tier-2 center approved at SLAC
• SLAC administration promoting user groups
• Future participation from SLAC without break-up

5
Where were we 3 years ago?
Dec 2003

• BABAR analysis
• Charmed baryon studies getting started in
  earnest
• (mass spectra for a few ?c0/?c modes in 13
  fb-1,
• not corrected for efficiency)
• First look at pentaquark searches in same
  final states
• BABAR service work
• L1 trigger upgrade preparations in full swing
• ILC
• Concept of PFA outlined simulation studies
  just
• starting on the first piece (MIP finding)

6
Invited Talks at Conferences

• Cornell Seminar (M.Charles BABAR Physics) Spring
  07, Cornell, NY
• scheduled
• Sixth KEK Topical Conference (P. Behera) February
  07, KEK, Japan,
• scheduled
• 21st International Workshop on Weak Interactions
  and neutrinos
• (P. Behera) January 07, Kolkata, India,
  scheduled
• International Workshop XXXV on Gross Properties
  of Nuclei and Nuclear Excitations (M. Charles)
  January 07, Hirschegg, Austria, scheduled
• Meeting of APS Topical Group on Hadronic Physics
  (V. Ziegler Hyperon and Hyperon Resonance
  Properties from Charm Baryon Decays in BABAR)
  October 06, Nashville, TN
• SLAC Seminar (V. Ziegler Hyperon and Hyperon
  Resonance Properties from Charm Baryon Decays in
  BABAR) October 06, SLAC, CA
• ICHEP06 (U. Mallik hot topics from BABAR),
  Jul-Aug 06, Moscow, Russia
• Vancouver Linear Collider Workshop (M. Charles
  PFA Framework and Status) July 06, Vancouver,
  Canada

7
Invited Talks at Conferences contd

• Conference on International Particle and Nuclear
  Physics(U. Mallik Recent News of Charm and
  Charmonia from BABAR), May 06, San Juan, Puerto
  Rico
• APS meeting (X. Chai B-decays into Charm Baryon
  Pairs) April 06, Dulles, TX
• European ILC Meeting (M. Charles PFA Status)
  April 06, Cambridge, UK
• LCWS06 (U. Mallik PFA Status in North America)
  March 06, Bangalore, India
• ALCPG Workshop (M. Charles Status and Results
  for the Structural PFA) January 06, Boluder, CO
• Cascade Workshop (V. Ziegler Hyperon Properties
  from Charm Baryon Decays) November 05, J-Lab, VA
• Hadron 05 (V. Ziegler Charm Baryon Studies at
  BABAR) August 05, Rio de Janeiro, Brazil
• ALCPG and ILC Snowmass Workshop (M. Charles
  Clustering of Hadronic Showers with a Structural
  Algorithm) August 05, Snowmass, CO
• ALCPG and ILC Snowmass Workshop (N. Meyers
  Electromagnetic Shower Reconstruction for the
  Si-Detector) August 05, Snowmass, CO
• LC 2005 (U. Mallik New Results in Hadronic
  Spectroscopy) July 05, Cairn, Australia

8
Invited Talks at Conferences contd

• Division of Particles and Fields (X. Chai The
  BABAR Level 1 Drift Chamber Trigger Upgrade)
  August 04, Riverside, CA
• Division of Particles and Fields (W. Mader
  Status of Particle Flow Studies in the EM
  Calorimeter in SiD) August 04, Riverside, CA
• ICHEP04 (M. Charles Charm Decays at BABAR)
  August 04, Beijing, China
• LCWS 2004 (W. Mader Status of Particle Flow
  Studies in the EM Calorimeter in SiD) July 04,
  Victoria, CA
• APS 2004 (M. Charles Studies of ?c0 and ?c at
  BABAR) April 04, Denver, CO
• APS 2004 (X. Chai Charm Baryons, ?c0 and ?c,
  Studies at BABAR) April 04, Denver, CO
• Seminars
• U. of Iowa (U. Mallik Iowas Work at BABAR)
  spring 2006
• U. of Illinois, Champagne (U. Mallik New
  Results from BABAR) fall 2005
• and other talk opportunities (e.g. M. Charles
  and P. Behera both offered talks at ICHEP06)

9
Publications Recent and Pending

• Production and Decay of ?c0 at BABAR, Phys. Rev.
  Lett. 95 142003, 2005
• Measurement of spin of of the ?- Hyperon at
  BABAR, Phys. Rev. Lett. 97 112001, 2006
• Observation of an Excited Charm Baryon ?c
  Decaying into ?c?, accepted by Phys. Rev. Lett.
  for publication
• Observation of B ??K and B0 ??K0
  below ?c threshold, accepted by Phys. Rev. Lett.
  for publication
• A study of production and decays of ?c baryons at
  BABAR, hep-ex/050711, contributed to LP05 (in
  BABAR review committee)
• The mass, width and spin of the ?(1690)
  resonance, hep-ex/0607043, contributed to ICHEP06
  (in preparation for submission to Phys. Rev. D)
• ?c Production at BABAR, hex-ex/0607086,
  contributed to ICHEP06 (to be prepared for
  publication)
• Production and Determination of Properties of
  ?(1530) (in progress)
• B ?c?c and ?c?cK , (in preparation for
  submission to Phys. Rev. D)

10
Hilightes of BABAR Analysis
Ground states of charm baryons
11
Charm Baryon Studies

• ?c0 Study surprise
• B ? ?c0 production as large as cc ? ?c0
  production
• b ? ccs production non-negligible?
• ?c0 Study first observation of B ? ?c0
• First Observation of ?c0 ? ?c0 ?

12
Spin Measurement

• ?- in ?c0 ? ?-K decay angular distribution
  (helicity formalism)
• Then verify with ?c0 ? ?-? angular distribution
• ?(1690) in ?c ? LK0 K decay
• Use isobar model (?(1690) ? LK0 , a0(980) ?
  K0K)
• Fit Dalitz plot distribution including
  interference
• X(1530)0 in Lc ? X- p K decay
• X(1530)0 ? X- p

13

• Examine implications of W- spin hypotheses
• for angular distribution of L from W- decay

?(L) 1/2
q
quantization axis
?(K) 0
J 1/2 m 1/2 m - 1/2
?(K) 0
?
l(W) 1/2 l(W) - 1/2
W- inherits the spin projections of the Xc0
since, no orbital angular momentum projection
w.r.t. quantization axis in ?c0 decay
? diagonal density matrix element for W- spin
projection li l(W) is rl
i

• Initial helicity, ?i ? (W) 1/2
• Final state helicity, ?f ? (L) -
  ?(pseudoscalar) 1/2
• Decay amplitude for O- ? ? K-

Transition matrix element does not depend on
li Wigner-Eckart theorem
?Total Intensity
density matrix element for W- spin projection
li density matrix element for charm
baryon parent
14
Spin measurement of W- from Xc0 ? W- K, W- ?
L K- decays
Data 116 fb-1
Background-Subtracted Efficiency-Corrected
Similar conclusion from Wc0 ? W-p, W- ? LK-
decays
ConclusionJ(W-) 3/2 assumingJ(Xc0) 1/2
JW 1/2
? Fit Prob 10 -17
JW 3/2
? Fit Prob 0.64
? Fit Prob 10 -7
JW 5/2
JW 7/2 also excluded angular distribution
increases more steeply near cosq 1
and has (2 JW
-2) turning points.
8
15
Legendre Polynomial Moments in Spin Determination

For W- spin J, the previous angular distributions
can be written
9
16
Illustration of the Use of Legendre Polynomial
Moments in Spin Determination

(will prove
useful later)
wj v10 P2(cosq) from Xc0 signal region

• - ?
• signal

W- ? signal
? efficiency-corrected , mass-sideband-subtract
ed unweighted m(L K-) distribution in data
efficiency-corrected v10 P2 (cosq) weighted
efficiency-corrected (7/ v2) P4 (cosq) weighted
17
Study of b ? ccs decay
Inconsistency in the MC and data p distribution
MC only has b ? cud
Search B decays into charm-baryon-anti-charm-baryo
n pair
B ? ?c?c and B ? ?c ?c K (9 modes X. Chais
thesis )
18
International Linear Collider

• Particle Flow Algorithm (PFA)
• Needs highly segmented calorimeter
• Follow charged track into Cal and isolate shower
• Replace charged track shower energy by tracker
  momentum
• ?2 ?charged2 ?neutral2 ?confusion2
• assuming ?confusion 0, and,
• ?charged negligible
• ?2 ?neutral2
• almost 60 energy is charged hadrons, 25 in
  ?s and 13 in neutral hadrons (excluding ?0) at
  the Z-pole
• much improved resolution

19
ATLAS Activities
TRT, SCT, PIXEL
20
Pixel Overview

• 3 Barrel Layers, 2 3 Disks.
• 3 hit-tracking up to ? 2.5.
• Good impact parameter resolution due to B-Layer
  at 5cm.
• Total of 1744 modules.
• 46080 channels per modules 80 million channels.

21
Where do we stand?

• The Pixel detector is not fully assembled yet.
• End cap is fully assembled but needs to be tested
  with full software.
• We are involved in the system test (one end cap
  fully integrated).
• This is the first time that we are trying to run
  the complete system.

22
End cap in the test stand
End cap
Cooling copper pipe
23
End cap test stand
Opto-Board
Fiber readout
Service Quarter Panel
24
Iowas contribution

• Testing the readout LV power supply module used
  for system test. ( Prafulla )
• One of the experts to run the cooling system for
  pixel system. ( Prafulla )
• Running the system test and taking shift for the
  run ( 8 hour duration ). ( Prafulla, Alex
  learning )
• DAQ software development and testing and actively
  involved in commissioning. ( Alex and Prafulla )

25
Summary and Conclusion

• Active in BABAR and productive in physics
  analysis
• Jump-started in the ATLAS experiment in
  Silicon-Pixel
• Prafulla at CERN since end of September for 3
  months
• (has been an excellent addition to the group)
• Alex Schreiner joined him at CERN in early
  November
• ILC work progressing well
• Mats leadership and contribution acknowledged
  as central
• Veronique and Xuedong expect to graduate next
  semester
• Current group size needs maintaining