3 <title>Beam Parameters</title>
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30 <h2>Beam Parameters</h2>
32 The settings on this page relate to the beam identities and energies,
33 to a beam momentum spread and to a beam interaction spot.
34 As always, momenta and energies are to be given in units of GeV,
35 and of space and time in mm.
37 <h3>Incoming beams</h3>
39 There are two ways to set the identities and energies of the two incoming
40 beam particles. One is to use the <code>init()</code> method with no
41 arguments. Then the settings variables below will be read and used. The
42 alternative is to call <code><?php $filepath = $_GET["filepath"];
43 echo "<a href='ProgramFlow.php?filepath=".$filepath."' target='page'>";?>init(...)</a></code>
44 with arguments that provide this information. Then you need not use the
45 variables below (although it would still be possible). Note that, if nothing
46 is done, you will default to LHC at 14 TeV.
49 Currently the beam particles must be either a hadron pair or a lepton
50 pair. In the former category <i>p p</i> and <i>pbar p</i>
51 combinations dominate, but it is also possible to combine with
52 <i>pi^+</i>, <i>pi^-</i> and <i>pi^0</i>. In the latter
53 <i>e^+ e^-</i> and <i>mu^+ mu^-</i> would be the most useful
54 combinations, but also others should work if combined with an
55 appropriate hard process.
57 <br/><br/><table><tr><td><strong>Beams:idA </td><td></td><td> <input type="text" name="1" value="2212" size="20"/> (<code>default = <strong>2212</strong></code>)</td></tr></table>
58 The PDG <code>id</code> code for the first incoming particle.
60 <br/><i>2212 = p</i>, <i>-2212 = pbar</i>,
61 <br/><i>211 = pi^+</i>, <i>-211 = pi^-</i>, <i>111 = pi^0</i>,
62 <br/><i>990 = Pomeron</i> (used in diffractive machinery;
63 here mainly for debug purposes),
64 <br/><i>11 = e^-</i>, <i>-11 = e^+</i>,
65 <br/><i>13 = mu^-</i>, <i>-13 = mu^+</i>,
66 <br/>and a few more leptons/neutrinos in a few combinations.
69 <br/><br/><table><tr><td><strong>Beams:idB </td><td></td><td> <input type="text" name="2" value="2212" size="20"/> (<code>default = <strong>2212</strong></code>)</td></tr></table>
70 The PDG <code>id</code> code for the second incoming particle.
73 <br/><br/><table><tr><td><strong>Beams:frameType </td><td> (<code>default = <strong>1</strong></code>; <code>minimum = 1</code>; <code>maximum = 4</code>)</td></tr></table>
74 Choice of frame for the two colliding particles.
76 <input type="radio" name="3" value="1" checked="checked"><strong>1 </strong>: the beams are colliding in their CM frame, and therefore only the CM energy needs to be provided, see <code>Beams:eCM</code> below. <br/>
77 <input type="radio" name="3" value="2"><strong>2 </strong>: the beams are back-to-back, but with different energies, see <code>Beams:eA</code> and <code>Beams:eB</code> below. This option could also be used for fixed-target configurations. <br/>
78 <input type="radio" name="3" value="3"><strong>3 </strong>: the beams are not back-to-back, and therefore the three-momentum of each incoming particle needs to be specified, see <code>Beams:pxA</code> through <code>Beams:pzB</code> below. <br/>
79 <input type="radio" name="3" value="4"><strong>4 </strong>: the beam and event information is stored in a Les Houches Event File, see <code>Beams:LHEF</code> below. <br/>
81 <br/><br/><table><tr><td><strong>Beams:eCM </td><td></td><td> <input type="text" name="4" value="14000." size="20"/> (<code>default = <strong>14000.</strong></code>; <code>minimum = 10.</code>)</td></tr></table>
82 Collision CM energy, to be set if <code>Beams:frameType</code> = 1.
85 <br/><br/><table><tr><td><strong>Beams:eA </td><td></td><td> <input type="text" name="5" value="7000." size="20"/> (<code>default = <strong>7000.</strong></code>; <code>minimum = 0.</code>)</td></tr></table>
86 The energy of the first incoming particle, moving in the
87 <i>+z </i>direction, to be set if <code>Beams:frameType</code> = 2.
88 If the particle energy is smaller than its mass
89 it is assumed to be at rest.
92 <br/><br/><table><tr><td><strong>Beams:eB </td><td></td><td> <input type="text" name="6" value="7000." size="20"/> (<code>default = <strong>7000.</strong></code>; <code>minimum = 0.</code>)</td></tr></table>
93 The energy of the second incoming particle, moving in the
94 <i>-z</i> direction, to be set if <code>Beams:frameType</code> = 2.
95 If the particle energy is smaller than its mass
96 it is assumed to be at rest.
99 <br/><br/><table><tr><td><strong>Beams:pxA </td><td></td><td> <input type="text" name="7" value="0." size="20"/> (<code>default = <strong>0.</strong></code>)</td></tr></table>
100 The <i>p_x</i> component of the first incoming particle,
101 to be set if <code>Beams:frameType</code> = 3.
104 <br/><br/><table><tr><td><strong>Beams:pyA </td><td></td><td> <input type="text" name="8" value="0." size="20"/> (<code>default = <strong>0.</strong></code>)</td></tr></table>
105 The <i>p_y</i> component of the first incoming particle,
106 to be set if <code>Beams:frameType</code> = 3.
109 <br/><br/><table><tr><td><strong>Beams:pzA </td><td></td><td> <input type="text" name="9" value="7000." size="20"/> (<code>default = <strong>7000.</strong></code>)</td></tr></table>
110 The <i>p_z</i> component of the first incoming particle,
111 to be set if <code>Beams:frameType</code> = 3.
114 <br/><br/><table><tr><td><strong>Beams:pxB </td><td></td><td> <input type="text" name="10" value="0." size="20"/> (<code>default = <strong>0.</strong></code>)</td></tr></table>
115 The <i>p_x</i> component of the second incoming particle,
116 to be set if <code>Beams:frameType</code> = 3.
119 <br/><br/><table><tr><td><strong>Beams:pyB </td><td></td><td> <input type="text" name="11" value="0." size="20"/> (<code>default = <strong>0.</strong></code>)</td></tr></table>
120 The <i>p_y</i> component of the second incoming particle,
121 to be set if <code>Beams:frameType</code> = 3.
124 <br/><br/><table><tr><td><strong>Beams:pzB </td><td></td><td> <input type="text" name="12" value="-7000." size="20"/> (<code>default = <strong>-7000.</strong></code>)</td></tr></table>
125 The <i>p_z</i> component of the second incoming particle,
126 to be set if <code>Beams:frameType</code> = 3.
129 <br/><br/><table><tr><td><strong>Beams:LHEF </td><td></td><td> <input type="text" name="13" value="void" size="20"/> (<code>default = <strong>void</strong></code>)</td></tr></table>
130 The name of a Les Houches Event File,
131 to be set if <code>Beams:frameType</code> = 4.
134 <h3>Beam momentum spread</h3>
136 This framework currently is intended for a modest beam spread, such as
137 experienced at hadron colliders. Thus it can be safely assumed that the
138 physics does not change over the CM energy range probed, so that the
139 parameters of the physics initialization at the nominal energy can be
140 used as is. Currently it can <b>not</b> be used for the more extensive
141 energy spread expected at linear <i>e^+ e^-</i> colliders. Also,
142 any attempt to combine it with external Les Houches input of
143 parton-level events is at own risk.
146 On this page you can set the momentum spread according to a simple
147 Gaussian distribution. If you instead want a more sophisticated
148 parametrization, you can write and link your own
149 <code><?php $filepath = $_GET["filepath"];
150 echo "<a href='BeamShape.php?filepath=".$filepath."' target='page'>";?>BeamShape</a></code> class.
152 <br/><br/><strong>Beams:allowMomentumSpread</strong> <input type="radio" name="14" value="on"><strong>On</strong>
153 <input type="radio" name="14" value="off" checked="checked"><strong>Off</strong>
154 (<code>default = <strong>off</strong></code>)<br/>
155 Allow the beam momenta to be smeared around their initialization
159 <br/><br/><table><tr><td><strong>Beams:sigmaPxA </td><td></td><td> <input type="text" name="15" value="0." size="20"/> (<code>default = <strong>0.</strong></code>; <code>minimum = 0.</code>)</td></tr></table>
160 The width of a Gaussian distribution of the <i>p_x</i> spread of the
161 first incoming particle.
164 <br/><br/><table><tr><td><strong>Beams:sigmaPyA </td><td></td><td> <input type="text" name="16" value="0." size="20"/> (<code>default = <strong>0.</strong></code>; <code>minimum = 0.</code>)</td></tr></table>
165 The width of a Gaussian distribution of the <i>p_y</i> spread of the
166 first incoming particle.
169 <br/><br/><table><tr><td><strong>Beams:sigmaPzA </td><td></td><td> <input type="text" name="17" value="0." size="20"/> (<code>default = <strong>0.</strong></code>; <code>minimum = 0.</code>)</td></tr></table>
170 The width of a Gaussian distribution of the <i>p_z</i> spread of the
171 first incoming particle.
174 <br/><br/><table><tr><td><strong>Beams:maxDevA </td><td></td><td> <input type="text" name="18" value="5." size="20"/> (<code>default = <strong>5.</strong></code>; <code>minimum = 0.</code>)</td></tr></table>
175 The triply Gaussian distribution <i>(p_x, p_y, p_z)</i> is restricted to
176 a maximal total deviation from the nominal values <i>(p_x0, p_y0, p_z0)</i>
177 for the first incoming particle, like
179 (p_x - p_x0)^2/sigma_px^2 + (p_y - p_y0)^2/sigma_py^2 +
180 (p_z - p_z0)^2/sigma_pz^2 < maxDev^2
182 (Note the absence of a factor 2 in the denominator, unlike the Gaussians
183 used to pick <i>(p_x, p_y, p_z)</i>.)
186 <br/><br/><table><tr><td><strong>Beams:sigmaPxB </td><td></td><td> <input type="text" name="19" value="0." size="20"/> (<code>default = <strong>0.</strong></code>; <code>minimum = 0.</code>)</td></tr></table>
187 The width of a Gaussian distribution of the <i>p_x</i> spread of the
188 second incoming particle.
191 <br/><br/><table><tr><td><strong>Beams:sigmaPyB </td><td></td><td> <input type="text" name="20" value="0." size="20"/> (<code>default = <strong>0.</strong></code>; <code>minimum = 0.</code>)</td></tr></table>
192 The width of a Gaussian distribution of the <i>p_y</i> spread of the
193 second incoming particle.
196 <br/><br/><table><tr><td><strong>Beams:sigmaPzB </td><td></td><td> <input type="text" name="21" value="0." size="20"/> (<code>default = <strong>0.</strong></code>; <code>minimum = 0.</code>)</td></tr></table>
197 The width of a Gaussian distribution of the <i>p_z</i> spread of the
198 second incoming particle.
201 <br/><br/><table><tr><td><strong>Beams:maxDevB </td><td></td><td> <input type="text" name="22" value="5." size="20"/> (<code>default = <strong>5.</strong></code>; <code>minimum = 0.</code>)</td></tr></table>
202 The triply Gaussian distribution <i>(p_x, p_y, p_z)</i> is restricted to
203 a maximal total deviation from the nominal values <i>(p_x0, p_y0, p_z0)</i>,
204 for the second incoming particle, like
206 (p_x - p_x0)^2/sigma_px^2 + (p_y - p_y0)^2/sigma_py^2 +
207 (p_z - p_z0)^2/sigma_pz^2 < maxDev^2
209 (Note the absence of a factor 2 in the denominator, unlike the Gaussians
210 used to pick <i>(p_x, p_y, p_z)</i>.)
213 <h3>Beam interaction vertex</h3>
215 On this page you can set the spread of the interaction vertex according to
216 a simple Gaussian distribution. If you instead want a more sophisticated
217 parametrization, you can write and link your own
218 <code><?php $filepath = $_GET["filepath"];
219 echo "<a href='BeamShape.php?filepath=".$filepath."' target='page'>";?>BeamShape</a></code> class.
221 <br/><br/><strong>Beams:allowVertexSpread</strong> <input type="radio" name="23" value="on"><strong>On</strong>
222 <input type="radio" name="23" value="off" checked="checked"><strong>Off</strong>
223 (<code>default = <strong>off</strong></code>)<br/>
224 Allow the interaction vertex of the two colliding beams to be smeared.
225 If off, then the vertex is set to be the origin.
228 <br/><br/><table><tr><td><strong>Beams:sigmaVertexX </td><td></td><td> <input type="text" name="24" value="0." size="20"/> (<code>default = <strong>0.</strong></code>; <code>minimum = 0.</code>)</td></tr></table>
229 The width of a Gaussian distribution of the <i>x</i> location of the
233 <br/><br/><table><tr><td><strong>Beams:sigmaVertexY </td><td></td><td> <input type="text" name="25" value="0." size="20"/> (<code>default = <strong>0.</strong></code>; <code>minimum = 0.</code>)</td></tr></table>
234 The width of a Gaussian distribution of the <i>y</i> location of the
238 <br/><br/><table><tr><td><strong>Beams:sigmaVertexZ </td><td></td><td> <input type="text" name="26" value="0." size="20"/> (<code>default = <strong>0.</strong></code>; <code>minimum = 0.</code>)</td></tr></table>
239 The width of a Gaussian distribution of the <i>z</i> location of the
243 <br/><br/><table><tr><td><strong>Beams:maxDevVertex </td><td></td><td> <input type="text" name="27" value="5." size="20"/> (<code>default = <strong>5.</strong></code>; <code>minimum = 0.</code>)</td></tr></table>
244 The triply Gaussian distribution of interaction vertex position
245 <i>(x, y, z)</i> is restricted to a maximal total deviation from the
248 x^2/sigma_x^2 + y^2/sigma_y^2 + z^2/sigma_z^2 < maxDevVertex^2
250 (Note the absence of a factor 2 in the denominator, unlike the Gaussians
251 used to pick <i>(x, y, z)</i>.)
254 <br/><br/><table><tr><td><strong>Beams:sigmaTime </td><td></td><td> <input type="text" name="28" value="0." size="20"/> (<code>default = <strong>0.</strong></code>; <code>minimum = 0.</code>)</td></tr></table>
255 The width of a Gaussian distribution of the collision time (in units of
256 mm/c). Note that, if the above space parametrization is viewed as the
257 effect of two incoming beams along the <i>+-z</i> axis, with each beam
258 having a Gaussian spread, then the spread of the time would also become
259 a Gaussian with the same width as the <i>z</i> one (times the
260 velocity of the beams, which we expect is close to unity). For flexibility
261 we have not enforced any such relation, however.
264 <br/><br/><table><tr><td><strong>Beams:maxDevTime </td><td></td><td> <input type="text" name="29" value="5." size="20"/> (<code>default = <strong>5.</strong></code>; <code>minimum = 0.</code>)</td></tr></table>
265 The collision time is restricted to be in the range
266 <i>|t| < sigma_t * maxDevTime</i>.
270 The distributions above are all centered at the origin. It is also
271 possible to shift the above distributions to be centered around another
272 nominal position. You must have <code>Beams:allowVertexSpread = on</code>
273 to use this possibility.
275 <br/><br/><table><tr><td><strong>Beams:offsetVertexX </td><td></td><td> <input type="text" name="30" value="0." size="20"/> (<code>default = <strong>0.</strong></code>)</td></tr></table>
276 The <i>x</i> location of the interaction vertex is centered at this value.
279 <br/><br/><table><tr><td><strong>Beams:offsetVertexY </td><td></td><td> <input type="text" name="31" value="0." size="20"/> (<code>default = <strong>0.</strong></code>)</td></tr></table>
280 The <i>y</i> location of the interaction vertex is centered at this value.
283 <br/><br/><table><tr><td><strong>Beams:offsetVertexZ </td><td></td><td> <input type="text" name="32" value="0." size="20"/> (<code>default = <strong>0.</strong></code>)</td></tr></table>
284 The <i>z</i> location of the interaction vertex is centered at this value.
287 <br/><br/><table><tr><td><strong>Beams:offsetTime </td><td></td><td> <input type="text" name="33" value="0." size="20"/> (<code>default = <strong>0.</strong></code>)</td></tr></table>
288 The time <i>t</i> of the interaction vertex is centered at this value.
291 <input type="hidden" name="saved" value="1"/>
294 echo "<input type='hidden' name='filepath' value='".$_GET["filepath"]."'/>"?>
296 <table width="100%"><tr><td align="right"><input type="submit" value="Save Settings" /></td></tr></table>
301 if($_POST["saved"] == 1)
303 $filepath = $_POST["filepath"];
304 $handle = fopen($filepath, 'a');
306 if($_POST["1"] != "2212")
308 $data = "Beams:idA = ".$_POST["1"]."\n";
309 fwrite($handle,$data);
311 if($_POST["2"] != "2212")
313 $data = "Beams:idB = ".$_POST["2"]."\n";
314 fwrite($handle,$data);
316 if($_POST["3"] != "1")
318 $data = "Beams:frameType = ".$_POST["3"]."\n";
319 fwrite($handle,$data);
321 if($_POST["4"] != "14000.")
323 $data = "Beams:eCM = ".$_POST["4"]."\n";
324 fwrite($handle,$data);
326 if($_POST["5"] != "7000.")
328 $data = "Beams:eA = ".$_POST["5"]."\n";
329 fwrite($handle,$data);
331 if($_POST["6"] != "7000.")
333 $data = "Beams:eB = ".$_POST["6"]."\n";
334 fwrite($handle,$data);
336 if($_POST["7"] != "0.")
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339 fwrite($handle,$data);
341 if($_POST["8"] != "0.")
343 $data = "Beams:pyA = ".$_POST["8"]."\n";
344 fwrite($handle,$data);
346 if($_POST["9"] != "7000.")
348 $data = "Beams:pzA = ".$_POST["9"]."\n";
349 fwrite($handle,$data);
351 if($_POST["10"] != "0.")
353 $data = "Beams:pxB = ".$_POST["10"]."\n";
354 fwrite($handle,$data);
356 if($_POST["11"] != "0.")
358 $data = "Beams:pyB = ".$_POST["11"]."\n";
359 fwrite($handle,$data);
361 if($_POST["12"] != "-7000.")
363 $data = "Beams:pzB = ".$_POST["12"]."\n";
364 fwrite($handle,$data);
366 if($_POST["13"] != "void")
368 $data = "Beams:LHEF = ".$_POST["13"]."\n";
369 fwrite($handle,$data);
371 if($_POST["14"] != "off")
373 $data = "Beams:allowMomentumSpread = ".$_POST["14"]."\n";
374 fwrite($handle,$data);
376 if($_POST["15"] != "0.")
378 $data = "Beams:sigmaPxA = ".$_POST["15"]."\n";
379 fwrite($handle,$data);
381 if($_POST["16"] != "0.")
383 $data = "Beams:sigmaPyA = ".$_POST["16"]."\n";
384 fwrite($handle,$data);
386 if($_POST["17"] != "0.")
388 $data = "Beams:sigmaPzA = ".$_POST["17"]."\n";
389 fwrite($handle,$data);
391 if($_POST["18"] != "5.")
393 $data = "Beams:maxDevA = ".$_POST["18"]."\n";
394 fwrite($handle,$data);
396 if($_POST["19"] != "0.")
398 $data = "Beams:sigmaPxB = ".$_POST["19"]."\n";
399 fwrite($handle,$data);
401 if($_POST["20"] != "0.")
403 $data = "Beams:sigmaPyB = ".$_POST["20"]."\n";
404 fwrite($handle,$data);
406 if($_POST["21"] != "0.")
408 $data = "Beams:sigmaPzB = ".$_POST["21"]."\n";
409 fwrite($handle,$data);
411 if($_POST["22"] != "5.")
413 $data = "Beams:maxDevB = ".$_POST["22"]."\n";
414 fwrite($handle,$data);
416 if($_POST["23"] != "off")
418 $data = "Beams:allowVertexSpread = ".$_POST["23"]."\n";
419 fwrite($handle,$data);
421 if($_POST["24"] != "0.")
423 $data = "Beams:sigmaVertexX = ".$_POST["24"]."\n";
424 fwrite($handle,$data);
426 if($_POST["25"] != "0.")
428 $data = "Beams:sigmaVertexY = ".$_POST["25"]."\n";
429 fwrite($handle,$data);
431 if($_POST["26"] != "0.")
433 $data = "Beams:sigmaVertexZ = ".$_POST["26"]."\n";
434 fwrite($handle,$data);
436 if($_POST["27"] != "5.")
438 $data = "Beams:maxDevVertex = ".$_POST["27"]."\n";
439 fwrite($handle,$data);
441 if($_POST["28"] != "0.")
443 $data = "Beams:sigmaTime = ".$_POST["28"]."\n";
444 fwrite($handle,$data);
446 if($_POST["29"] != "5.")
448 $data = "Beams:maxDevTime = ".$_POST["29"]."\n";
449 fwrite($handle,$data);
451 if($_POST["30"] != "0.")
453 $data = "Beams:offsetVertexX = ".$_POST["30"]."\n";
454 fwrite($handle,$data);
456 if($_POST["31"] != "0.")
458 $data = "Beams:offsetVertexY = ".$_POST["31"]."\n";
459 fwrite($handle,$data);
461 if($_POST["32"] != "0.")
463 $data = "Beams:offsetVertexZ = ".$_POST["32"]."\n";
464 fwrite($handle,$data);
466 if($_POST["33"] != "0.")
468 $data = "Beams:offsetTime = ".$_POST["33"]."\n";
469 fwrite($handle,$data);
478 <!-- Copyright (C) 2010 Torbjorn Sjostrand -->