(r8) PiENu < Main

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---++ !PiENu

The PIENU experiment at TRIUMF (Vancouver, Canada) aims at precisely measuring the pion decay branching ratio (&#960;+ &#8594; e&#957;)/(&#960; &#8594;&#956;&#957;).  
The current experimental value for this ratio is 20 times less precise than the theoretical calculation done within the SM, leaving a large window in which non-standard physics - new interactions or exotic particles - can be involved. Or, on the other hand, improved precision that would confirm the SM would set tighter constraints on new physics scenarios.

%TOC%

---+++ PPE People

Currently, David Britton, Main.DanProtopopescu and Ian Skillicorn are contributing to this [[https://pienu.triumf.ca/collaborators][experiment]].

---+++ Shift Schedule

Available here: http://pienu02.triumf.ca/pienu_shifts/index.php

---+++ Documentation

   * Official website at Triumf: http://pienu.triumf.ca/
   * [[%ATTACHURL%/TalkINPC.pdf][INPC 2010 talk]] by Chloé Malbrunot
   * [[%ATTACHURL%/PIENU_proposal.pdf][PIENU Proposal]]

---+++ Code compilation

The MC code was obtained from =svn=  (pienu02.triumf.ca/pienumc/trunk) and unpacked on the UI. Specific versions of CLHEP (2.0.4.2) and Geant4 (4.9.0.3.p02) were installed in the user directory in =~/packages/=.
Detailed download and compilation instructions for CLHEP, Geant4 and the main pienu code were provided by Aleksey Sher via email (May 2011).

---+++ Monte Carlo

MC run using recommended settings, 100k events (to check):

   * Output of default MC run =pienu pienu.mac= : [[http://ppewww.physics.gla.ac.uk/~protopop/pienu/mc/root/run1.root][run1.root]]
   * Output from =MCtoData run1out.root run1.root= : [[http://ppewww.physics.gla.ac.uk/~protopop/pienu/mc/root/run1out.root][run1out.root]] ([[http://ppewww.physics.gla.ac.uk/~protopop/pienu/mc/root/stdout2.txt][stdout]])

---+++ Bhabha events tagging 

In MC, this is done via a code snippet added by Chloe in =SteppingAction.cc=:
<verbatim>
//Chloe's addition (in SteppingAction.cc)
    if (theParticleName == "e+" 
        && thePostVolume == "/pienu/Target" 
        && theProcessName == "eIoni") {
        runAction->SBhabha(postEnergy);
     // G4cout << postEnergy/MeV << G4endl;
    } 
</verbatim>
However, this only selects Bhabha scattering events happening in the target volume.

---+++ Reproducing plots from Chloe's thesis

The data tree produced by =MCtoData= contains numerous new branches, which can be useful for this analysis. A first step is trying to identify these branches and reproduce some of the most important plots from Chloe's thesis.
These PDFs contain our plots:
   * [[%ATTACHURL%/Plots-2012-06-26.pdf][Plots-2012-06-26.pdf]]: Plots reproducing figures 1.2, 5.1 and 5.19

The ROOT macros used to draw these plots are attached [[%ATTACHURL%/macros.tgz][here]].

Attachments

Topic attachments
I	Attachment	History	Action	Size	Date	Who	Comment
pdf	PIENU_proposal.pdf	r1	manage	381.7 K	2012-05-04 - 15:11	DanProtopopescu	PIENU Proposal
pdf	Plots-2012-06-26.pdf	r1	manage	1030.5 K	2012-06-27 - 11:07	DanProtopopescu	Plots reproducing figures 1.2, 5.1 and 5.19
pdf	TalkINPC.pdf	r1	manage	3132.1 K	2012-05-04 - 15:08	DanProtopopescu	INPC 2010 talk by Chloé Malbrunot
tgz	macros.tgz	r1	manage	4.0 K	2012-06-27 - 11:10	DanProtopopescu	Analysis macros (initial versions)

Topic revision: r8 - 2013-02-06 - DanProtopopescu

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