ATLAS+CMS discussion of “Computers in the search for the Higgs Boson”

for JCSS

Ian Fisk (FNAL) + Norman McCubbin (RAL) 26th November 2013

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Where have we got to…???

• As last time (October): not as far advanced as we hoped for…

• We have:– Outline, attached to indico page: fewer missing names than

last time;– SVN repository: has been “exercised” a bit. Ian has updated

(?) the (rather old) latex version used by SVN. – cms-atlas-jcss mailing list. (PLEASE SUBSCRIBE, if you

haven’t done so!)– There’s now a twiki page (email 23rd November) for other

material that may be interesting or useful: https://twiki.cern.ch/twiki/bin/viewauth/CMSPublic/JointJCSSPaper

ATLAS+CMS:JCSS 25 Oct 2013

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Introduction: Chapters 1 +2

• There has been some discussion of what’s in Chapters 1+2, and in what order.

• Very rough text and ideas are in the SVN repository (under ’overview’ – Ch2).

• Chapter 1 will contain: – Introduction to particle physics and “Higgs” at a level suitable

for the “numerate (eg computer scientist) lay-person”.– The fact that pp collisions have many possible outcomes, and

some (eg Higgs production) are very rare. (Rate= sigma x Lumi etc) Also the idea that the mass of a short-lived particle can be inferred from measurement of its decay products. (“E=mc2” etc)

– Sufficient introduction and key parameters of LHC machine and the detectors to motivate:

– Discussion of the LHC “computing challenge(s)”. ATLAS+CMS:JCSS 26 Nov 2013

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Introduction: Chapters 1 +2

• Chapter 2 will contain: – A brief description of the “flow” from either real LHC collisions

or simulation through to “publication” and/or physics results.– Hence the following terminology and ideas get introduced in

this chapter, but detailed descriptions will come in the later chapters:

• Collision rate, pile-up, simulation (Monte Carlo), DAQ and trigger, data rates and volumes, on-line, off-line, reconstruction, calibration, alignment, distributed processing and analysis, physics analysis, internal checking of potential results.

ATLAS+CMS:JCSS 25 Oct 2013

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Introduction: Chapters 1 +2

• Flavour of (so not final) figures or pictures that will be in Chapters 1 +2 :

ATLAS+CMS:JCSS 25 Oct 2013

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Introduction: Chapters 1 +2

• NOT FINAL figures or pictures that will be in Chapters 1 +2 :

ATLAS+CMS:JCSS 25 Oct 2013