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+<title>Total Cross Sections</title>
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+?>
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+<form method='post' action='TotalCrossSections.php'>
+
+<h2>Total Cross Sections</h2>
+
+The <code>SigmaTotal</code> class returns the total, elastic, diffractive
+and nondiffractive cross sections in hadronic collisions, and also the
+slopes of the <i>d(sigma)/dt</i> distributions. Most of the parametrizations
+used are from [<a href="Bibliography.php" target="page">Sch94, Sch97</a>] which borrows some of the total cross
+sections from [<a href="Bibliography.php" target="page">Don92</a>]. If you use the MBR (Minimum Bias Rockefeller)
+model [<a href="Bibliography.php" target="page">Cie12</a>], <code>Diffraction:PomFlux = 5</code>, this model
+contains its own parametrizations of all cross sections in <i>p p</i>
+and <i>pbar p</i> collisions.
+
+<p/>
+There are strong indications that the currently implemented diffractive
+cross section parametrizations, which should be in reasonable agreement
+with data at lower energies, overestimate the diffractive rate at larger
+values. If you wish to explore this (or other) aspect, it is possible to
+override the cross section values in two different ways. The first offers
+(almost) complete freedom, but needs to be defined separately for each
+CM energy, while the second introduces a simpler parametrized damping.
+The two cannot be combined. Furthermore the Coulomb term for elastic
+scattering, which by default is off, can be switched on.
+
+<p/>
+The allowed combinations of incoming particles are <i>p + p</i>,
+<i>pbar + p</i>, <i>pi+ + p</i>, <i>pi- + p</i>,
+<i>pi0/rho0 + p</i>, <i>phi + p</i>, <i>J/psi + p</i>,
+<i>rho + rho</i>, <i>rho + phi</i>, <i>rho + J/psi</i>,
+<i>phi + phi</i>, <i>phi + J/psi</i>, <i>J/psi + J/psi</i>.
+The strong emphasis on vector mesons is related to the description
+of <i>gamma + p</i> and <i>gamma + gamma</i> interactions in a
+Vector Dominance Model framework (which will not be available for some
+time to come, so this is a bit of overkill). Nevertheless, the sections
+below, with allowed variations, are mainly intended to make sense for
+<i>p + p</i>.
+
+<h3>Central diffraction</h3>
+
+Central diffraction (CD), a.k.a. double Pomeron exchange (DPE), was not
+part of the framework in [<a href="Bibliography.php" target="page">Sch94</a>]. It has now been added for
+multiparticle states, i.e. excluding the resonance region below 1 GeV
+mass, as well as other exclusive states, but only for <i>p p</i> or
+<i>pbar p</i>. It uses the same proton-Pomeron vertex as in single
+diffraction, twice, to describe <i>x_Pomeron</i> and <i>t</i> spectra.
+This fixes the energy dependence, which has been integrated and
+parametrized. The absolute normalization has been left open, however.
+Furthermore, since CD has not been included in previous tunes to data,
+a special flag is available to reproduce the old behaviour (with due
+complications when one does not want to do this).
+
+<br/><br/><table><tr><td><strong>SigmaTotal:sigmaAXB2TeV </td><td></td><td> <input type="text" name="1" value="1.5" size="20"/> (<code>default = <strong>1.5</strong></code>; <code>minimum = 0.</code>)</td></tr></table>
+The CD cross section for <i>p p</i> and <i>pbar p</i> collisions,
+normalized to its value at 2 TeV CM energy, expressed in mb. The energy
+dependence is then parametrized, and behaves roughly like
+<i>ln^1.5(s)</i>. Is used for the options
+<code>Diffraction:PomFlux = 1 - 4</code>, while the MBR model
+(<code>= 5</code>) has its own parametrization.
+
+
+<br/><br/><strong>SigmaTotal:zeroAXB</strong> <input type="radio" name="2" value="on"><strong>On</strong>
+<input type="radio" name="2" value="off" checked="checked"><strong>Off</strong>
+ (<code>default = <strong>off</strong></code>)<br/>
+several existing <?php $filepath = $_GET["filepath"];
+echo "<a href='Tunes.php?filepath=".$filepath."' target='page'>";?>tunes</a> do not include CD.
+An inclusion of a nonvanishing CD cross section directly affects
+the minbias phenomenology (even if not dramatically), and so
+this flag is used to switch off the CD cross section in such tunes.
+You can switch it back on <i>after</i> the selection of a tune, if you
+so wish. This option has no effect for the MBR model
+(<code>Diffraction:PomFlux = 5</code>), where the CD cross section
+has been included from the onset.
+
+
+<h3>Set cross sections</h3>
+
+<br/><br/><strong>SigmaTotal:setOwn</strong> <input type="radio" name="3" value="on"><strong>On</strong>
+<input type="radio" name="3" value="off" checked="checked"><strong>Off</strong>
+ (<code>default = <strong>off</strong></code>)<br/>
+Allow a user to set own cross sections by hand; on/off = true/false.
+
+
+<p/>
+When <code>SigmaTotal:setOwn = on</code>, the user is expected to set
+values for the corresponding cross sections:
+
+<br/><br/><table><tr><td><strong>SigmaTotal:sigmaTot </td><td></td><td> <input type="text" name="4" value="80." size="20"/> (<code>default = <strong>80.</strong></code>; <code>minimum = 0.</code>)</td></tr></table>
+Total cross section in mb.
+
+
+<br/><br/><table><tr><td><strong>SigmaTotal:sigmaEl </td><td></td><td> <input type="text" name="5" value="20." size="20"/> (<code>default = <strong>20.</strong></code>; <code>minimum = 0.</code>)</td></tr></table>
+Elastic cross section in mb.
+
+
+<br/><br/><table><tr><td><strong>SigmaTotal:sigmaXB </td><td></td><td> <input type="text" name="6" value="8." size="20"/> (<code>default = <strong>8.</strong></code>; <code>minimum = 0.</code>)</td></tr></table>
+Single Diffractive cross section <i>A + B -> X + B</i> in mb.
+
+
+<br/><br/><table><tr><td><strong>SigmaTotal:sigmaAX </td><td></td><td> <input type="text" name="7" value="8." size="20"/> (<code>default = <strong>8.</strong></code>; <code>minimum = 0.</code>)</td></tr></table>
+Single Diffractive cross section <i>A + B -> A + X</i> in mb.
+
+
+<br/><br/><table><tr><td><strong>SigmaTotal:sigmaXX </td><td></td><td> <input type="text" name="8" value="4." size="20"/> (<code>default = <strong>4.</strong></code>; <code>minimum = 0.</code>)</td></tr></table>
+Double Diffractive cross section <i>A + B -> X_1 + X_2</i> in mb.
+
+
+<br/><br/><table><tr><td><strong>SigmaTotal:sigmaAXB </td><td></td><td> <input type="text" name="9" value="1." size="20"/> (<code>default = <strong>1.</strong></code>; <code>minimum = 0.</code>)</td></tr></table>
+Central Diffractive cross section <i>A + B -> A + X + B</i> in mb.
+
+
+<p/>
+Note that the total cross section subtracted by the elastic and various
+diffractive ones gives the inelastic nondiffractive cross section,
+which therefore is not set separately. If this cross section evaluates
+to be negative the internal parametrizations are used instead of the
+ones here. However, since the nondiffractive inelastic cross section
+is what makes up the minimum-bias event class, and plays a major role
+in the description of multiparton interactions, it is important that a
+consistent set is used.
+
+<h3>Dampen diffractive cross sections</h3>
+
+As already noted, unitarization effects may dampen the rise of diffractive
+cross sections relative to the default parametrizations. The settings
+here allows one way to introduce a dampening, which is used in some
+of the existing <?php $filepath = $_GET["filepath"];
+echo "<a href='Tunes.php?filepath=".$filepath."' target='page'>";?>tunes</a>.
+
+<br/><br/><strong>SigmaDiffractive:dampen</strong> <input type="radio" name="10" value="on"><strong>On</strong>
+<input type="radio" name="10" value="off"><strong>Off</strong>
+ (<code>default = <strong>no</strong></code>)<br/>
+Allow a user to dampen diffractive cross sections; on/off = true/false.
+
+
+<p/>
+When <code>SigmaDiffractive:dampen = on</code>, the three diffractive
+cross sections are damped so that they never can exceed the respective
+values below. Specifically, if the standard parametrization gives
+the cross section <i>sigma_old(s)</i> and a fixed <i>sigma_max</i>
+is set, the actual cross section becomes <i>sigma_new(s)
+= sigma_old(s) * sigma_max / (sigma_old(s) + sigma_max)</i>.
+This reduces to <i>sigma_old(s)</i> at low energies and to
+<i>sigma_max</i> at high ones. Note that the asymptotic value
+is approached quite slowly, however.
+
+<br/><br/><table><tr><td><strong>SigmaDiffractive:maxXB </td><td></td><td> <input type="text" name="11" value="15." size="20"/> (<code>default = <strong>15.</strong></code>; <code>minimum = 0.</code>)</td></tr></table>
+The above <i>sigma_max</i> for <i>A + B -> X + B</i> in mb.
+
+
+<br/><br/><table><tr><td><strong>SigmaDiffractive:maxAX </td><td></td><td> <input type="text" name="12" value="15." size="20"/> (<code>default = <strong>15.</strong></code>; <code>minimum = 0.</code>)</td></tr></table>
+The above <i>sigma_max</i> for <i>A + B -> A + X</i> in mb.
+
+
+<br/><br/><table><tr><td><strong>SigmaDiffractive:maxXX </td><td></td><td> <input type="text" name="13" value="15." size="20"/> (<code>default = <strong>15.</strong></code>; <code>minimum = 0.</code>)</td></tr></table>
+The above <i>sigma_max</i> for <i>A + B -> X_1 + X_2</i> in mb.
+
+
+<br/><br/><table><tr><td><strong>SigmaDiffractive:maxAXB </td><td></td><td> <input type="text" name="14" value="3." size="20"/> (<code>default = <strong>3.</strong></code>; <code>minimum = 0.</code>)</td></tr></table>
+The above <i>sigma_max</i> for <i>A + B -> A + X + B</i> in mb.
+
+
+<p/>
+As above, a reduced diffractive cross section automatically translates
+into an increased nondiffractive one, such that the total (and elastic)
+cross section remains fixed.
+
+
+<h3>Set elastic cross section</h3>
+
+<p/>
+In the above option the <i>t</i> slopes are based on the internal
+parametrizations. In addition there is no Coulomb-term contribution
+to the elastic (or total) cross section, which of course becomes
+infinite if this contribution is included. If you have switched on
+<code>SigmaTotal:setOwn</code> you can further switch on a machinery
+to include the Coulomb term, including interference with the conventional
+strong-interaction Pomeron one [<a href="Bibliography.php" target="page">Ber87</a>]. Then the elastic cross
+section is no longer taken from <code>SigmaTotal:sigmaEl</code> but
+derived from the parameters below and <code>SigmaTotal:sigmaTot</code>,
+using the optical theorem. The machinery is only intended to be used for
+<i>p p</i> and <i>pbar p</i> collisions. The description of
+diffractive events, and especially their slopes, remains unchanged.
+
+<br/><br/><strong>SigmaElastic:setOwn</strong> <input type="radio" name="15" value="on"><strong>On</strong>
+<input type="radio" name="15" value="off"><strong>Off</strong>
+ (<code>default = <strong>no</strong></code>)<br/>
+Allow a user to set parameters for the normalization and shape of the
+elastic cross section the by hand; yes/no = true/false.
+
+
+<br/><br/><table><tr><td><strong>SigmaElastic:bSlope </td><td></td><td> <input type="text" name="16" value="18." size="20"/> (<code>default = <strong>18.</strong></code>; <code>minimum = 0.</code>)</td></tr></table>
+the slope <i>b</i> of the strong-interaction term <i>exp(bt)</i>,
+in units of GeV^-2.
+
+
+<br/><br/><table><tr><td><strong>SigmaElastic:rho </td><td></td><td> <input type="text" name="17" value="0.13" size="20"/> (<code>default = <strong>0.13</strong></code>; <code>minimum = -1.</code>; <code>maximum = 1.</code>)</td></tr></table>
+the ratio of the real to the imaginary parts of the nuclear scattering
+amplitude.
+
+
+<br/><br/><table><tr><td><strong>SigmaElastic:lambda </td><td></td><td> <input type="text" name="18" value="0.71" size="20"/> (<code>default = <strong>0.71</strong></code>; <code>minimum = 0.1</code>; <code>maximum = 2.</code>)</td></tr></table>
+the main parameter of the electric form factor
+<i>G(t) = lambda^2 / (lambda + |t|)^2</i>, in units of GeV^2.
+
+
+<br/><br/><table><tr><td><strong>SigmaElastic:tAbsMin </td><td></td><td> <input type="text" name="19" value="5e-5" size="20"/> (<code>default = <strong>5e-5</strong></code>; <code>minimum = 1e-10</code>)</td></tr></table>
+since the Coulomb contribution is infinite a lower limit on
+<i>|t|</i> must be set to regularize the divergence,
+in units of GeV^2.
+
+
+<br/><br/><table><tr><td><strong>SigmaElastic:phaseConst </td><td></td><td> <input type="text" name="20" value="0.577" size="20"/> (<code>default = <strong>0.577</strong></code>)</td></tr></table>
+The Coulomb term is taken to contain a phase factor
+<i>exp(+- i alpha phi(t))</i>, with + for <i>p p</i> and - for
+<i>pbar p</i>, where <i>phi(t) = - phaseConst - ln(-B t/2)</i>.
+This constant is model dependent [<a href="Bibliography.php" target="page">Cah82</a>].
+
+
+<input type="hidden" name="saved" value="1"/>
+
+<?php
+echo "<input type='hidden' name='filepath' value='".$_GET["filepath"]."'/>"?>
+
+<table width="100%"><tr><td align="right"><input type="submit" value="Save Settings" /></td></tr></table>
+</form>
+
+<?php
+
+if($_POST["saved"] == 1)
+{
+$filepath = $_POST["filepath"];
+$handle = fopen($filepath, 'a');
+
+if($_POST["1"] != "1.5")
+{
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+fwrite($handle,$data);
+}
+if($_POST["2"] != "off")
+{
+$data = "SigmaTotal:zeroAXB = ".$_POST["2"]."\n";
+fwrite($handle,$data);
+}
+if($_POST["3"] != "off")
+{
+$data = "SigmaTotal:setOwn = ".$_POST["3"]."\n";
+fwrite($handle,$data);
+}
+if($_POST["4"] != "80.")
+{
+$data = "SigmaTotal:sigmaTot = ".$_POST["4"]."\n";
+fwrite($handle,$data);
+}
+if($_POST["5"] != "20.")
+{
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+fwrite($handle,$data);
+}
+if($_POST["6"] != "8.")
+{
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+fwrite($handle,$data);
+}
+if($_POST["7"] != "8.")
+{
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+fwrite($handle,$data);
+}
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+{
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+fwrite($handle,$data);
+}
+if($_POST["9"] != "1.")
+{
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+fwrite($handle,$data);
+}
+if($_POST["10"] != "no")
+{
+$data = "SigmaDiffractive:dampen = ".$_POST["10"]."\n";
+fwrite($handle,$data);
+}
+if($_POST["11"] != "15.")
+{
+$data = "SigmaDiffractive:maxXB = ".$_POST["11"]."\n";
+fwrite($handle,$data);
+}
+if($_POST["12"] != "15.")
+{
+$data = "SigmaDiffractive:maxAX = ".$_POST["12"]."\n";
+fwrite($handle,$data);
+}
+if($_POST["13"] != "15.")
+{
+$data = "SigmaDiffractive:maxXX = ".$_POST["13"]."\n";
+fwrite($handle,$data);
+}
+if($_POST["14"] != "3.")
+{
+$data = "SigmaDiffractive:maxAXB = ".$_POST["14"]."\n";
+fwrite($handle,$data);
+}
+if($_POST["15"] != "no")
+{
+$data = "SigmaElastic:setOwn = ".$_POST["15"]."\n";
+fwrite($handle,$data);
+}
+if($_POST["16"] != "18.")
+{
+$data = "SigmaElastic:bSlope = ".$_POST["16"]."\n";
+fwrite($handle,$data);
+}
+if($_POST["17"] != "0.13")
+{
+$data = "SigmaElastic:rho = ".$_POST["17"]."\n";
+fwrite($handle,$data);
+}
+if($_POST["18"] != "0.71")
+{
+$data = "SigmaElastic:lambda = ".$_POST["18"]."\n";
+fwrite($handle,$data);
+}
+if($_POST["19"] != "5e-5")
+{
+$data = "SigmaElastic:tAbsMin = ".$_POST["19"]."\n";
+fwrite($handle,$data);
+}
+if($_POST["20"] != "0.577")
+{
+$data = "SigmaElastic:phaseConst = ".$_POST["20"]."\n";
+fwrite($handle,$data);
+}
+fclose($handle);
+}
+
+?>
+</body>
+</html>
+
+<!-- Copyright (C) 2012 Torbjorn Sjostrand -->
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