Page MenuHomeHEPForge
Files F8308628

UPCconsiderations.html
No OneTemporary
Actions

UPCconsiderations.html
View Options

<!--
//==============================================================================
// UPCcondiderations.html
//
// Copyright (C) 2010-2013 Tobias Toll and Thomas Ullrich
//
// This file is part of Sartre version: 1.1
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation.
// This program is distributed in the hope that it will be useful,
// but without any warranty; without even the implied warranty of
// merchantability or fitness for a particular purpose. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
//
// Author: Tobias Toll
// Last update:
// $Date: 2013-01-14 16:47:38 -0500 (Mon, 14 Jan 2013) $
// $Author: thomas.ullrich@bnl.gov $
//==============================================================================
-->
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html
PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en_US" lang="en_US">
<head>
<title>Sartre - Generating Ultra-Peripheral Collisions</title>
<meta http-equiv="Content-type" content="text/html; charset=UTF-8" /> <link href="sartre.css" rel="stylesheet" type="text/css" />
</head>
<body>
<table border="0" cellpadding="0" cellspacing="0" width="100%">
<tr>
<td width="120" align="left" valign="top"><img src="images/sartreLogo.png" alt="" border="0" align="right" /></td>
<td width="10">&nbsp;&nbsp;</td>
<td align="left" valign="middle" class="postheader"><a href="index.html"><font color="#004faf">Home</font></a>&nbsp;&middot;
<a href="overview.html"><font color="#004faf">Overview</font></a>&nbsp;&middot;<font color="#004faf"> <a href="usersGuide.html">Users
Guide</a></font>&nbsp;&middot;
<a href="referenceGuide.html"><font color="#004faf">Reference Guide</font> </a></td></tr>
</table>
<h1 class="title">Generating Ultra-Peripheral Collisions</h1>
<p>
There are a few things to consider while writing a user program
for simulation of ultra peripheral hadron-hadron collisions (UPC):
</p>
<ul>
<li>
In Sar<em>t</em>re, the beam particle emitting the photon is
always the beam particle coming from the right, <em>i.e.</em> with
negative momentum in the <var>z</var> direction. For UPC events
with symmetric beams one then needs to reflect the entire event
in <var>the xy</var>-plane
in half of the events, preferably chosen at random.
</li>
<li>
When running UPC for symmetric beams, the cross-section given
by calling <code><a href="refSartre.html#totalCrossSection">Sartre::totalCrossSection()</a></code> has to
be multiplied by a factor 2.
</li>
<li>
When running with asymmetric beams, <em>e.g. </em>proton-gold, one has
to run events with A=1 and UPCA=197, as well as events with
A=197 and UPCA=1. These events then has to be weighted by
respective cross-section. This can be avoided if one can
make experimental cuts such that one of the processes dominates
the events. </li>
</ul>
<address><div align="center">
<table border="0" cellspacing="0" width="100%"><tbody><tr class="address">
<td align="left" width="40%">&nbsp;</td>
<td align="center" width="20%">&nbsp;</td>
<td align="right" width="40%"><div align="right"><br>Last Update:
<!-- #BeginDate format:Am1 -->February 21, 2013<!-- #EndDate -->
</div></td>
</tr></tbody></table></div></address>
</body></html>

File Metadata

Mime Type
text/html
Expires
Sat, Dec 21, 12:40 PM (1 d, 17 h)
Storage Engine
blob
Storage Format
Raw Data
Storage Handle
4001291
Default Alt Text
UPCconsiderations.html (4 KB)

Event Timeline