The LHCb Experimentpresented at
Digital Divide and HEPGRID WorkshopRio de Janeiro, Feb 2004
Tatsuya Nakada
CERN and Swiss Federal Institute of Technology Lausanne (EPFL),
Switzerland
CP Violation
We know two examples which showsmatter world anti-matter world.
CP symmetry is violated !!
Evolution of Universe
matter
anti-matter
amount of matter = amount of anti-matter
our universeonly with matter
big bang
We see no anti nucleus in the cosmic ray.We se no rays from pp annihilation in space.
ConclusionNo evidence of anti matter in our domain of universe.
(~20 Mps 108 light-years)
Can our universe be “inverse” Emmental Cheese?Difficult!!
Most likely, no anti matter in our universe.(~3000 Mps 1010 light-years)
Void
matter
anti matter
What do we know?
Two key numbers
Number of baryons (NB)
Number of photons (N)~
cosmic microwave background radiation
stars, gas etc.
Number of baryons now but
NBNB
NBNB
_
_ ~
1 baryon out of did not annihilate and survived.
How can we generate
from NB NB initial condition for Big Bang at t?
NBNB
NBNB
_
_ ~
Necessary conditions:1) Baryon number violations:
initial and final baryon numbers are different.2) C and CP violation:
partial decay widths are different.3) Out of equilibrium:
no reversing reaction installing the initial state.(A.Sakharov, 1967)
_
Discovery of CP violation in particle physics: J.H. Christenson et al., PRL 1964
KL X
KL
p = p + p
= angle between pKL and p
If X = 0, p = pKL: cos = 1If X 0, p pKL: cos 1
cos
KL
m () < mK
m () = mK
m () > mK
Why KL is CP?
neutral kaondecay time distribution
anti-neutral kaondecay time distribution
CP violation
CPLEAR Experiment (1999)
CP violation in a more intuitive way!
Initial K0 CP transformation Initial K0
BABAR and Belle Experiments (2002)
t = 0
J/ KSB0
J/ KSB0
CP
t
similarly...
CP violation
How to generate CP violation?
1) Since CPT is respected, CP is like T2) T transformation is like making complex conjugation:
eiEt T eiEt 3) T transformation to the Hamiltonian operator H
H T H
if H H, eiH t eiH*t eiH t
T i.e. CP
Standard Model and CP violation
U =uct
D =dsb
Up type quarkspinor field
Q =
Down type quarkspinor field
Q =
Weak interaction neutral currentcharged current:
W
dL
cL
W
Vcd coupling
example
there are = 9 V’s
Strong interaction gluonsElectromagnetic interaction photons
Electroweak theory with 3 families cannaturally accommodate CP violation
in the charged current induced interactionsthrough the complex
Cabibbo-Kobayashi-Maskawa quarkmixing matrix V, with
4 parameters.
One family (u, d): V realTwo families (u, d), (c, s): V realThree families (u, d), (c, s), (t, b): V can be complex
Problem!!
CP violation inthe K and B meson decays
canbe explained by
the Standard Model.
New source for CP violation beyond the Standard Model in the particle world?
CP violation inthe universe
cannot be explained by
the Standard Model.
NBNB
NBNB
_
_ ~ Universe:
NBNB
NBNB
_
_ ~Standard Model:
New source of CP violation
X
q
q
complex coupling constant
X: Super Symmetric Particles, Multi-Higgs doublets, etc.
CP transformation containscomplex conjugation:
eiH t eiH*t
i.e. H* H CP violation
Search for unexpected effects in CP violation and rare decaysin Bu, Bd, Bs, Bc and b-baryons.
At LHC
p7 TeV= cal
1g of those p’s = 20 daysof US energy consumption
p7 TeV
LHCb detector
14 TeV mini bang
~100 times more B mesons then before
(Pre)History
-high luminosity e+e- B factoriesproposed at Cornell, DESY, KEK, Novosibirsk, PSI and SLAC
(since 1985…)realised at SLAC and KEK in 2000
-Idea to use high energy hadron machines as a source of B mesonsCERN pp collider, FNAL pp collider and LHC
Study of CP violation in B meson decays with high statistics
At LHCthree proto-experiments
GAJET (internal gas target), COBEX (collider mode) andLHB (extracted fix target beam)Expressions of Interest in Letters of Intent in
Joint experiment, LHCb: a forward spectrometer in collider mode
Letter of Intent in August 1995: encouragement from LHCCUFRJ group joined the LHCb Collaboration in 1997
S. Amato, J.R.T. de Mello, L. de Paula, M. Gandelman, J.H. Lopes and M. MarechalThe group has worked in the DELPHI experiment:
-data analysis, participating in detector construction by sending people at CERN (mainly PhD students)
Technical Proposal in February 1998 (S. Amato et al.)
recommended for an approval by LHCC in July 1998
b-b correlation
b
b
b
b
bb
Both b and b are in the spectrometer.
Draft Interim Memorandum of Understanding preparedTotal cost 86 MCHF (inclu. common fund 24.5 MCHF)
examined by the “CORE” committeeFunding discussion with the funding agencies by the
participating institutes.
Brazilian contribution in IMoU = 1.8 M CHF to the detector cost the detector (Muon system) + common fundwith an aim to construct a part of the muon chambers and contribute to the front-end electronics.
Total request to the funding agency (more than 1.8MCHF) includedparticipation to the R&Dpreparing the infrastructure for the construction and testtravel expense necessary for the installation, commissioning, data
taking, analysis meeting at CERN.
The idea was to ask for a global “project” money and manage locally. flexibility is important!
LHCb Resource Review Board (RRB) at CERN in September 1998Most of the funding agencies expressed positively theirfinancial contribution to the LHCb experimentBrazil: C. Aragao (UFRJ, head of the Physics Institute)
Extract from the Minutes;“C. Aragao reported the result of a visit to Brasilia with B. Marechal, the Brazilian representative on the Collaboration Board. The project was presented to the President of the Research Council (CNPq) who assured them that Brazil would contribute to the Common Fund should the experiment be approved and appear to consider the 0.824 MUSD request for detector construction to be reasonable. A more detailedrequest was subsequently submitted for seven annual contribution of 200 kUSD giving a total of 1.4 MUSD. No final comment has been received but, at the suggestion of the President, a workshop will be held in November in Rio, at which details of the experiment and the Brazilian part of the project will be presented to members of the CNPq. It is hoped to have a clearer indication of likely participationby then. C. Aragao said that, at the present time, he was authorised to say that Brazilwill participate in the Common Fund and will be studying participation in detectorconstruction at the level indicated in IMoU.”
Recommendation by LHCC and positive outcome from RRBCERN management approved the experiment in September 1998
Rio workshop on the LHCb experiment in January 1999organized by B. Marechal sponsored by CNPqpresentation by
T. Nakada: physics and organizationH.J. Hilke (Technical Coordinator): detectorJ. Christiansen (Electronics Coordinator) electronicsB. Schmidt (Muon system convener)
with participation by people from funding agencies (Rio and Brasilia)UFRJ management etc.
-very positively received.-understanding on how high energy physics manages itself increased.-a visit by the CNPq president to CERN in the occasion of the LHCb
RRB in April 1999 discussed.
LHCb magnet Technical Design Report: December 1999Superconductive coil Normal conductive coil16.5 MCHF (TP) 6MCF
LHCb MoU for the construction of the LHCb detector:finalised in November 2000
Detector Cost Funding expected from BrazilTP 86 MCHF ~70 MCHF 1.8 MCHFMoU 75 MCHF 73 MCHF 1.8 MCHF
February 2001 CBPF joined in the LHCb collaboration
September 2001LHCb Collaboration meeting was held in Ilha de Itacuruca, Brazil
October 2000, Visit to CNPq Brasilia by C. Aragao, B. Marechal and T. Nakada
July 2002Visit to CERN by the minister of State for Science and TechnologyJoint letter signed by the minister and DG for an extended cooperation.
All the subsystem TDR’s have been approved.Computing TDR to be submitted in 2005.Detector construction advancing…
Beam Pipe
Al window
Done by the LHC vacuum group
Magnet YokeAssembly of the lower half Plates are fixed by tie-rods
Lower half completed Assembly of the sides in progress
VELO
PrototypeTest
Constructionof VELO tanksupport stand
Si sensor test beam set-up Wake-field suppressor and RF foil
design constructed
RICH2
RICH2 exit window being made
Calorimeter
Ecal modules: 100% constructed Hcal modules: 30% constructed
SPD/Preshower production started
Muon system
First series production chambersFrascati CERN
Frascati Clean Room
panel on wiring machine
soldering table
assembly tables
At the time of LHCb RRB October 2003
MoU all signed except: Brazil ???Germany funding was guaranteed at the meetingPoland institute are receiving funding
Detector Cost Funding expected From BrazilTP (1998) 86 MCHF ~70 MCHF 1.8 MCHFMoU (2000) 75 MCHF 73 MCHF 1.8 MCHFOct. 2003 73 MCHF 71 MCHF since no clear
informationavailablewe had to assume0
Brazilian contribution to theconstruction of the experiment up to now
People visiting CERN, Marseille and Rome participating in the R&D, construction and testing of the experiment:
PhD students Muon chamberssupported by Muon Front-end electronics (VLSI)Brazil (~1 year) Muon trigger system
Postdocs and Muon chamberssenior scientists Muon electronics (test system)supported by Muon Experimental Control SystemBrazil (few weeks Core software development forto several months) and on- and offlinecollaboration(few weeks several months)
Work done at their home institute
CBPF Muon chamber test systemMuon electronics test systemCore software development
UFRJ Core software developmentLarge volume
MC data production
local expertise indetector physicists
Infrastructure i.e.equipped workshop andlaboratories
Small local funding forcomponents
local expertisephysicists with IT know-how
Infrastructuresmall CPU cluster
Small local funding forCPU
data production in 2003
Using LHCbhome made software toolsfor distributedproduction management.
Only you need isa reasonable-goodlink!No special middleware required.
Brazilian contribution to physicsPhysics performance study using MC data at home institute
UFRJ by PhD students and senior physicistsreconstruction of various decay modes
J/KS, J/ K*. DK* etc…reconstruction efficiency, signal over background, propertime resolution, etc…
Extraction of CP violation parameters and
Work is done in the framework of Physics Performance Task Force:short visitsweekly meeting with VRVS and/or phoneregular e-mail discussion
many LHCb notes, LHCb reoptimization TDR, conference talk
How do we plan to continue? Muon system
test of the front-end VLSI chips in Riotest of the front-end cards in Italy/CERNtest of wire chambers at CERNECS development in Rio/ItalyInstallation and commissioning at CERN
TriggerDevelopment of High Level Trigger algorithm in RioDevelopment of online system software framework in Rio
ComputingAnalysis framework software development in Rio/CERNData production in Rio
Physics study in Rio
Impressive list of contribution but there are serious problems…
No long term funding approved:Cannot fulfil “minimal” duty to the collaboration, i.e.
annual contribution to the Maintenance and Operation cost till theend of data analysis.
Difficult to under take a long term commitment.
No flexible funding was available:Travel cannot be arranged with a short notice (< 3 months)
Missing chances to give a talk in several conferencesCannot participate in many important meetings:
However, some progress is being made here…
Conclusions1) LHCb experiment will search for new physics beyond the Standard
Model in a complimentary way to ATLAS and CMS2) LHCb is consciously adjusting the project to the funding situation
without loosing physics performance3) Brazil has been in the collaboration since 1997. Originally
anticipated level of contribution to the detector construction (1.8 MCHF) does not seem to be realised. (MoU not signed)
4) Despite of this difficult situation, CPBF and UFRJ groups are making well appreciated contribution in developing test systems,on and offline software, data production and physics studies.
5) GRID is a great help but not a solution for the real problem.They still need a long term funding to cover the maintenance andoperation and trip to CERN to fully participate in the preparation,data taking, and physics analysis, i.e. exploiting their contribution(a few 100k CHF/year).
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