1
<chapter name="Particle Properties">
3
<h2>Particle Properties</h2>
5
A <code>Particle</code> corresponds to one entry/slot in the
6
event record. Its properties therefore is a mix of ones belonging
7
to a particle-as-such, like its identity code or four-momentum,
8
and ones related to the event-as-a-whole, like which mother it has.
11
What is stored for each particle is
13
<li>the identity code,</li>
14
<li>the status code,</li>
15
<li>two mother indices,</li>
16
<li>two daughter indices,</li>
17
<li>a colour and an anticolour index,</li>
18
<li>the four-momentum and mass,</li>
19
<li>the scale at which the particle was produced (optional),</li>
20
<li>the polarization/spin/helicity of the particle (optional),</li>
21
<li>the production vertex and proper lifetime (optional),</li>
22
<li>a pointer to the particle kind in the particle data table, and</li>
23
<li>a pointer to the whole particle data table.</li>
25
From these, a number of further quantities may be derived.
27
<h3>Basic output methods</h3>
29
The following member functions can be used to extract the most important
32
<method name="int Particle::id()">
33
the identity of a particle, according to the PDG particle codes
37
<method name="int Particle::status()">
38
status code. The status code includes information on how a particle was
39
produced, i.e. where in the program execution it was inserted into the
40
event record, and why. It also tells whether the particle is still present
41
or not. It does not tell how a particle disappeared, whether by a decay,
42
a shower branching, a hadronization process, or whatever, but this is
43
implicit in the status code of its daughter(s). The basic scheme is:
45
<li>status = +- (10 * i + j)</li>
46
<li> + : still remaining particles</li>
47
<li> - : decayed/branched/fragmented/... and not remaining</li>
48
<li> i = 1 - 9 : stage of event generation inside PYTHIA</li>
49
<li> i = 10 -19 : reserved for future expansion</li>
50
<li> i >= 20 : free for add-on programs</li>
51
<li> j = 1 - 9 : further specification</li>
53
In detail, the list of used or foreseen status codes is:
55
<li>11 - 19 : beam particles</li>
57
<li>11 : the event as a whole</li>
58
<li>12 : incoming beam</li>
59
<li>13 : incoming beam-inside-beam (e.g. <ei>gamma</ei>
60
inside <ei>e</ei>)</li>
61
<li>14 : outgoing elastically scattered</li>
62
<li>15 : outgoing diffractively scattered</li>
64
<li>21 - 29 : particles of the hardest subprocess</li>
66
<li>21 : incoming</li>
67
<li>22 : intermediate (intended to have preserved mass)</li>
68
<li>23 : outgoing</li>
70
<li>31 - 39 : particles of subsequent subprocesses</li>
72
<li>31 : incoming</li>
73
<li>32 : intermediate (intended to have preserved mass)</li>
74
<li>33 : outgoing</li>
75
<li>34 : incoming that has already scattered</li>
77
<li>41 - 49 : particles produced by initial-state-showers</li>
79
<li>41 : incoming on spacelike main branch</li>
80
<li>42 : incoming copy of recoiler</li>
81
<li>43 : outgoing produced by a branching</li>
82
<li>44 : outgoing shifted by a branching</li>
83
<li>45 : incoming rescattered parton, with changed kinematics
84
owing to ISR in the mother system (cf. status 34)</li>
85
<li>46 : incoming copy of recoiler when this is a rescattered
86
parton (cf. status 42)</li>
88
<li>51 - 59 : particles produced by final-state-showers</li>
90
<li>51 : outgoing produced by parton branching</li>
91
<li>52 : outgoing copy of recoiler, with changed momentum</li>
92
<li>53 : copy of recoiler when this is incoming parton,
93
with changed momentum</li>
94
<li>54 : copy of a recoiler, when in the initial state of a
95
different system from the radiator</li>
96
<li>55 : copy of a recoiler, when in the final state of a
97
different system from the radiator</li>
99
<li>61 - 69 : particles produced by beam-remnant treatment</li>
101
<li>61 : incoming subprocess particle with primordial <ei>kT</ei>
103
<li>62 : outgoing subprocess particle with primordial <ei>kT</ei>
105
<li>63 : outgoing beam remnant</li>
107
<li>71 - 79 : partons in preparation of hadronization process</li>
109
<li>71 : copied partons to collect into contiguous colour singlet</li>
110
<li>72 : copied recoiling singlet when ministring collapses to
111
one hadron and momentum has to be reshuffled</li>
112
<li>73 : combination of very nearby partons into one</li>
113
<li>74 : combination of two junction quarks (+ nearby gluons)
115
<li>75 : gluons split to decouple a junction-antijunction pair</li>
116
<li>76 : partons with momentum shuffled to decouple a
117
junction-antijunction pair </li>
118
<li>77 : temporary opposing parton when fragmenting first two
119
strings in to junction (should disappear again)</li>
120
<li>78 : temporary combined diquark end when fragmenting last
121
string in to junction (should disappear again)</li>
123
<li>81 - 89 : primary hadrons produced by hadronization process</li>
125
<li>81 : from ministring into one hadron</li>
126
<li>82 : from ministring into two hadrons</li>
127
<li>83, 84 : from normal string (the difference between the two
128
is technical, whether fragmented off from the top of the
129
string system or from the bottom, useful for debug only)</li>
130
<li>85, 86 : primary produced hadrons in junction frogmentation of
131
the first two string legs in to the junction,
132
in order of treatment</li>
134
<li>91 - 99 : particles produced in decay process, or by Bose-Einstein
137
<li>91 : normal decay products</li>
138
<li>92 : decay products after oscillation <ei>B0 <-> B0bar</ei> or
139
<ei>B_s0 <-> B_s0bar</ei></li>
140
<li>93, 94 : decay handled by external program, normally
141
or with oscillation</li>
142
<li>99 : particles with momenta shifted by Bose-Einstein effects
143
(not a proper decay, but bookkept as an <ei>1 -> 1</ei> such,
144
happening after decays of short-lived resonances but before
145
decays of longer-lived particles)</li>
147
<li>101 - 109 : particles in the handling of R-hadron production and
148
decay, i.e. long-lived (or stable) particles containing a very heavy
151
<li>101 : when a string system contains two such long-lived particles,
152
the system is split up by the production of a new q-qbar
153
pair (bookkept as decay chains that seemingly need not conserve
154
flavour etc., but do when considered together)</li>
155
<li>102 : partons rearranged from the long-lived particle end to prepare
156
for fragmentation from this end</li>
157
<li>103 : intermediate "half-R-hadron" formed when a colour octet particle
158
(like the gluino) has been fragmented on one side, but not yet on
160
<li>104 : an R-hadron</li>
161
<li>105 : partons or particles formed together with the R-hadron during
162
the fragmentation treatment</li>
163
<li>106 : subdivision of an R-hadron into its flavour content, with
164
momentum split accordingly, in preparation of the decay of
165
the heavy new particle, if it is unstable</li>
167
<li>111 - 199 : reserved for future expansion</li>
168
<li>201 - : free to be used by anybody</li>
172
<method name="int Particle::mother1()">
174
<methodmore name="int Particle::mother2()">
175
the indices in the event record where the first and last mothers are
176
stored, if any. There are five allowed combinations of <code>mother1</code>
177
and <code>mother2</code>:
179
<li><code>mother1 = mother2 = 0</code>: for lines 0 - 2, where line 0
180
represents the event as a whole, and 1 and 2 the two incoming
181
beam particles; </li>
182
<li><code>mother1 = mother2 > 0</code>: the particle is a "carbon copy"
183
of its mother, but with changed momentum as a "recoil" effect,
184
e.g. in a shower;</li>
185
<li><code>mother1 > 0, mother2 = 0</code>: the "normal" mother case, where
186
it is meaningful to speak of one single mother to several products,
187
in a shower or decay;</li>
188
<li><code>mother1 < mother2</code>, both > 0, for
189
<code>abs(status) = 81 - 86</code>: primary hadrons produced from the
190
fragmentation of a string spanning the range from <code>mother1</code>
191
to <code>mother2</code>, so that all partons in this range should be
192
considered mothers;</li>
193
<li><code>mother1 < mother2</code>, both > 0, except case 4: particles
194
with two truly different mothers, in particular the particles emerging
195
from a hard <ei>2 -> n</ei> interaction.</li>
197
<note>Note 1:</note> in backwards evolution of initial-state showers,
198
the mother may well appear below the daughter in the event record.
199
<note>Note 2:</note> the <code>motherList(i)</code> method of the
200
<code>Event</code> class returns a vector of all the mothers,
201
providing a uniform representation for all five cases.
204
<method name="int Particle::daughter1()">
206
<methodmore name="int Particle::daughter2()">
207
the indices in the event record where the first and last daughters
208
are stored, if any. There are five allowed combinations of
209
<code>daughter1</code> and <code>daughter2</code>:
211
<li><code>daughter1 = daughter2 = 0</code>: there are no daughters
213
<li><code>daughter1 = daughter2 > 0</code>: the particle has a
214
"carbon copy" as its sole daughter, but with changed momentum
215
as a "recoil" effect, e.g. in a shower;</li>
216
<li><code>daughter1 > 0, daughter2 = 0</code>: each of the incoming beams
217
has only (at most) one daughter, namely the initiator parton of the
218
hardest interaction; further, in a <ei>2 -> 1</ei> hard interaction,
219
like <ei>q qbar -> Z^0</ei>, or in a clustering of two nearby partons,
220
the initial partons only have this one daughter;</li>
221
<li><code>daughter1 < daughter2</code>, both > 0: the particle has
222
a range of decay products from <code>daughter1</code> to
223
<code>daughter2</code>;</li> <li><code>daughter2 < daughter1</code>,
224
both > 0: the particle has two separately stored decay products (e.g.
225
in backwards evolution of initial-state showers).</li>
227
<note>Note 1:</note> in backwards evolution of initial-state showers, the
228
daughters may well appear below the mother in the event record.
229
<note>Note 2:</note> the mother-daughter relation normally is reciprocal,
230
but not always. An example is hadron beams (indices 1 and 2), where each
231
beam remnant and the initiator of each multiparton interaction has the
232
respective beam as mother, but the beam itself only has the initiator
233
of the hardest interaction as daughter.
234
<note>Note 3:</note> the <code>daughterList(i)</code> method of the
235
<code>Event</code> class returns a vector of all the daughters,
236
providing a uniform representation for all five cases. With this method,
237
also all the daughters of the beams are caught, with the initiators of
238
the basic process given first, while the rest are in no guaranteed order
239
(since they are found by a scanning of the event record for particles
240
with the beam as mother, with no further information).
243
<method name="int Particle::col()">
245
<methodmore name="int Particle::acol()">
246
the colour and anticolour tags, Les Houches Accord <ref>Boo01</ref>
247
style (starting from tag 101 by default, see below).
248
<note>Note:</note> in the preliminary implementation of colour sextets
249
(exotic BSM particles) that exists since PYTHIA 8.150, a negative
250
anticolour tag is interpreted as an additional positive colour tag,
254
<method name="double Particle::px()">
256
<methodmore name="double Particle::py()">
258
<methodmore name="double Particle::pz()">
260
<methodmore name="double Particle::e()">
261
the particle four-momentum components.
264
<method name="Vec4 Particle::p()">
265
the particle four-momentum vector, with components as above.
268
<method name="double Particle::m()">
269
the particle mass, stored with a minus sign (times the absolute value)
270
for spacelike virtual particles.
273
<method name="double Particle::scale()">
274
the scale at which a parton was produced, which can be used to restrict
275
its radiation to lower scales in subsequent steps of the shower evolution.
276
Note that scale is linear in momenta, not quadratic (i.e. <ei>Q</ei>,
280
<method name="double Particle::pol()">
281
the polarization/spin/helicity of a particle. Currently Pythia does not
282
use this variable for any internal operations, so its meaning is not
283
uniquely defined. The LHA standard sets <code>SPINUP</code> to be the
284
cosine of the angle between the spin vector and the 3-momentum of the
285
decaying particle in the lab frame, i.e. restricted to be between +1
286
and -1. A more convenient choice could be the same quantity in the rest
287
frame of the particle production, either the hard subprocess or the
288
mother particle of a decay. Unknown or unpolarized particles should
289
be assigned the value 9.
292
<method name="double Particle::xProd()">
294
<methodmore name="double Particle::yProd()">
296
<methodmore name="double Particle::zProd()">
298
<methodmore name="double Particle::tProd()">
299
the production vertex coordinates, in mm or mm/c.
302
<method name="Vec4 Particle::vProd()">
303
The production vertex four-vector. Note that the components of a
304
<code>Vec4</code> are named <code>px(), py(), pz() and e()</code>
305
which of course then should be reinterpreted as above.
308
<method name="double Particle::tau()">
309
the proper lifetime, in mm/c. It is assigned for all hadrons with
310
positive nominal <ei>tau</ei>, <ei>tau_0 > 0</ei>, because it can be used
311
by PYTHIA to decide whether a particle should or should not be allowed
312
to decay, e.g. based on the decay vertex distance to the primary interaction
316
<h3>Input methods</h3>
318
The same method names as above are also overloaded in versions that
319
set values. These have an input argument of the same type as the
320
respective output above, and are of type <code>void</code>.
323
There are also a few alternative methods for input:
325
<method name="void Particle::statusPos()">
327
<methodmore name="void Particle::statusNeg()">
328
sets the status sign positive or negative, without changing the absolute value.
331
<method name="void Particle::statusCode(int code)">
332
changes the absolute value but retains the original sign.
335
<method name="void Particle::mothers(int mother1, int mother2)">
336
sets both mothers in one go.
339
<method name="void Particle::daughters(int daughter1, int daughter2)">
340
sets both daughters in one go.
343
<method name="void Particle::cols(int col, int acol)">
344
sets both colour and anticolour in one go.
347
<method name="void Particle::p(double px, double py, double pz, double e)">
348
sets the four-momentum components in one go.
351
<method name="void Particle::vProd(double xProd, double yProd,
352
double zProd, double tProd)">
353
sets the production vertex components in one go.
356
<h3>Further output methods</h3>
359
In addition, a number of derived quantities can easily be obtained,
360
but cannot be set, such as:
362
<method name="int Particle::idAbs()">
363
the absolute value of the particle identity code.
366
<method name="int Particle::statusAbs()">
367
the absolute value of the status code.
370
<method name="bool Particle::isFinal()">
371
true for a remaining particle, i.e. one with positive status code,
372
else false. Thus, after an event has been fully generated, it
373
separates the final-state particles from intermediate-stage ones.
374
(If used earlier in the generation process, a particle then
375
considered final may well decay later.)
378
<method name="bool Particle::isRescatteredIncoming()">
379
true for particles with a status code -34, -45, -46 or -54, else false.
380
This singles out partons that have been created in a previous
381
scattering but here are bookkept as belonging to the incoming state
382
of another scattering.
385
<method name="bool Particle::hasVertex()">
386
production vertex has been set; if false then production at the origin
390
<method name="double Particle::m2()">
391
squared mass, which can be negative for spacelike partons.
394
<method name="double Particle::mCalc()">
396
<methodmore name="double Particle::m2Calc()">
397
(squared) mass calculated from the four-momentum; should agree
398
with <code>m(), m2()</code> up to roundoff. Negative for spacelike
402
<method name="double Particle::eCalc()">
403
energy calculated from the mass and three-momentum; should agree
404
with <code>e()</code> up to roundoff. For spacelike partons a
405
positive-energy solution is picked. This need not be the correct
406
one, so it is recommended not to use the method in such cases.
409
<method name="double Particle::pT()">
411
<methodmore name="double Particle::pT2()">
412
(squared) transverse momentum.
415
<method name="double Particle::mT()">
417
<methodmore name="double Particle::mT2()">
418
(squared) transverse mass. If <ei>m_T^2</ei> is negative, which can happen
419
for a spacelike parton, then <code>mT()</code> returns
420
<ei>-sqrt(-m_T^2)</ei>, by analogy with the negative sign used to store
424
<method name="double Particle::pAbs()">
426
<methodmore name="double Particle::pAbs2()">
427
(squared) three-momentum size.
430
<method name="double Particle::eT()">
432
<methodmore name="double Particle::eT2()">
433
(squared) transverse energy,
434
<ei>eT = e * sin(theta) = e * pT / pAbs</ei>.
437
<method name="double Particle::theta()">
439
<methodmore name="double Particle::phi()">
440
polar and azimuthal angle.
443
<method name="double Particle::thetaXZ()">
444
angle in the <ei>(p_x, p_z)</ei> plane, between <ei>-pi</ei> and
445
<ei>+pi</ei>, with 0 along the <ei>+z</ei> axis
448
<method name="double Particle::pPos()">
450
<methodmore name="double Particle::pNeg()">
454
<method name="double Particle::y()">
456
<methodmore name="double Particle::eta()">
457
rapidity and pseudorapidity.
460
<method name="double Particle::xDec()">
462
<methodmore name="double Particle::yDec()">
464
<methodmore name="double Particle::zDec()">
466
<methodmore name="double Particle::tDec()">
468
<methodmore name="Vec4 Particle::vDec()">
469
the decay vertex coordinates, in mm or mm/c. This decay vertex is
470
calculated from the production vertex, the proper lifetime and the
471
four-momentum assuming no magnetic field or other detector interference.
472
It can be used to decide whether a decay should be performed or not,
473
and thus is defined also for particles which PYTHIA did not let decay.
477
Each Particle contains a pointer to the respective
478
<code>ParticleDataEntry</code> object in the
479
<aloc href="ParticleDataScheme">particle data tables</aloc>.
480
This gives access to properties of the particle species as such. It is
481
there mainly for convenience, and should be thrown if an event is
482
written to disk, to avoid any problems of object persistency. Should
483
an event later be read back in, the pointer will be recreated from the
484
<code>id</code> code if the normal input methods are used. (Use the
485
<code><aloc href="EventRecord">Event::restorePtrs()</aloc></code> method
486
if your persistency scheme bypasses the normal methods.) This pointer is
487
used by the following member functions:
489
<method name="string Particle::name()">
490
the name of the particle.
493
<method name="string Particle::nameWithStatus()">
494
as above, but for negative-status particles the name is given in
495
brackets to emphasize that they are intermediaries.
498
<method name="int Particle::spinType()">
499
<ei>2 *spin + 1</ei> when defined, else 0.
502
<method name="double Particle::charge()">
504
<methodmore name="int Particle::chargeType()">
505
charge, and three times it to make an integer.
508
<method name="bool Particle::isCharged()">
510
<methodmore name="bool Particle::isNeutral()">
511
charge different from or equal to 0.
514
<method name="int Particle::colType()">
515
0 for colour singlets, 1 for triplets,
516
-1 for antitriplets and 2 for octets. (A preliminary implementation of
517
colour sextets also exists, using 3 for sextets and -3 for antisextets.)
520
<method name="double Particle::m0()">
521
the nominal mass of the particle, according to the data tables.
524
<method name="double Particle::mWidth()">
526
<methodmore name="double Particle::mMin()">
528
<methodmore name="double Particle::mMax()">
529
the width of the particle, and the minimum and maximum allowed mass value
530
for particles with a width, according to the data tables.
533
<method name="double Particle::mass()">
534
the mass of the particle, picked according to a Breit-Wigner
535
distribution for particles with width. It is different each time called,
536
and is therefore only used once per particle to set its mass
540
<method name="double Particle::constituentMass()">
541
will give the constituent masses for quarks and diquarks,
542
else the same masses as with <code>m0()</code>.
545
<method name="double Particle::tau0()">
546
the nominal lifetime <ei>tau_0 > 0</ei>, in mm/c, of the particle species.
547
It is used to assign the actual lifetime <ei>tau</ei>.
550
<method name="bool Particle::mayDecay()">
551
flag whether particle has been declared unstable or not, offering
552
the main user switch to select which particle species to decay.
555
<method name="bool Particle::canDecay()">
556
flag whether decay modes have been declared for a particle,
557
so that it could be decayed, should that be requested.
560
<method name="bool Particle::doExternalDecay()">
561
particles that are decayed by an external program.
564
<method name="bool Particle::isResonance()">
565
particles where the decay is to be treated as part of the hard process,
566
typically with nominal mass above 20 GeV (<ei>W^+-, Z^0, t, ...</ei>).
569
<method name="bool Particle::isVisible()">
570
particles with strong or electric charge, or composed of ones having it,
571
which thereby should be considered visible in a normal detector.
574
<method name="bool Particle::isLepton()">
575
true for a lepton or an antilepton (including neutrinos).
578
<method name="bool Particle::isQuark()">
579
true for a quark or an antiquark.
582
<method name="bool Particle::isGluon()">
586
<method name="bool Particle::isDiquark()">
587
true for a diquark or an antidiquark.
590
<method name="bool Particle::isParton()">
591
true for a gluon, a quark or antiquark up to the b (but excluding top),
592
and a diquark or antidiquark consisting of quarks up to the b.
595
<method name="bool Particle::isHadron()">
596
true for a hadron (made up out of normal quarks and gluons,
597
i.e. not for R-hadrons and other exotic states).
600
<method name="ParticleDataEntry& particleDataEntry()">
601
a reference to the ParticleDataEntry.
605
Not part of the <code>Particle</code> class proper, but obviously tightly
606
linked, are the two methods
608
<method name="double m(const Particle& pp1, const Particle& pp2)">
610
<methodmore name="double m2(const Particle& pp1, const Particle& pp2)">
611
the (squared) invariant mass of two particles.
614
<h3>Methods that perform operations</h3>
616
There are some further methods, some of them inherited from
617
<code>Vec4</code>, to modify the properties of a particle.
618
They are of little interest to the normal user.
620
<method name="void Particle::rescale3(double fac)">
621
multiply the three-momentum components by <code>fac</code>.
624
<method name="void Particle::rescale4(double fac)">
625
multiply the four-momentum components by <code>fac</code>.
628
<method name="void Particle::rescale5(double fac)">
629
multiply the four-momentum components and the mass by <code>fac</code>.
632
<method name="void Particle::rot(double theta, double phi)">
633
rotate three-momentum and production vertex by these polar and azimuthal
637
<method name="void Particle::bst(double betaX, double betaY, double betaZ)">
638
boost four-momentum and production vertex by this three-vector.
641
<method name="void Particle::bst(double betaX, double betaY, double betaZ,
643
as above, but also input the <ei>gamma</ei> value, to reduce roundoff errors.
646
<method name="void Particle::bst(const Vec4& pBst)">
647
boost four-momentum and production vertex by
648
<ei>beta = (px/e, py/e, pz/e)</ei>.
651
<method name="void Particle::bst(const Vec4& pBst, double mBst)">
652
as above, but also use <ei>gamma> = e/m</ei> to reduce roundoff errors.
655
<method name="void Particle::bstback(const Vec4& pBst)">
657
<methodmore name="void Particle::bstback(const Vec4& pBst, double mBst)">
658
as above, but with sign of boost flipped.
661
<method name="void Particle::rotbst(const RotBstMatrix& M)">
662
combined rotation and boost of the four-momentum and production vertex.
665
<method name="void Particle::offsetHistory( int minMother, int addMother,
666
int minDaughter, int addDaughter))">
667
add a positive offset to the mother and daughter indices, i.e.
668
if <code>mother1</code> is above <code>minMother</code> then
669
<code>addMother</code> is added to it, same with <code>mother2</code>,
670
if <code>daughter1</code> is above <code>minDaughter</code> then
671
<code>addDaughter</code> is added to it, same with <code>daughter2</code>.
674
<method name="void Particle::offsetCol( int addCol)">
675
add a positive offset to colour indices, i.e. if <code>col</code> is
676
positive then <code>addCol</code> is added to it, same with <code>acol</code>.
679
<h3>Constructors and operators</h3>
681
Normally a user would not need to create new particles. However, if
682
necessary, the following constructors and methods may be of interest.
684
<method name="Particle::Particle()">
685
constructs an empty particle, i.e. where all properties have been set 0
689
<method name="Particle::Particle(int id, int status = 0, int mother1 = 0,
690
int mother2 = 0, int daughter1 = 0, int daughter2 = 0, int col = 0,
691
int acol = 0, double px = 0., double py = 0., double pz = 0., double e = 0.,
692
double m = 0., double scale = 0., double pol = 9.)">
693
constructs a particle with the input properties provided, and non-provided
694
ones set 0 (9 for <code>pol</code>).
697
<method name="Particle::Particle(int id, int status, int mother1, int mother2,
698
int daughter1, int daughter2, int col, int acol, Vec4 p, double m = 0.,
699
double scale = 0., double pol = 9.)">
700
constructs a particle with the input properties provided, and non-provided
701
ones set 0 (9 for <code>pol</code>).
704
<method name="Particle::Particle(const Particle& pt)">
705
constructs an particle that is a copy of the input one.
708
<method name="Particle& Particle::operator=(const Particle& pt)">
709
copies the input particle.
712
<method name="void Particle::setPDTPtr()">
713
sets the pointer to the <code>ParticleData</code> objects,
714
i.e. to the full particle data table. Also calls <code>setPDEPtr</code>
718
<method name="void Particle::setPDEPtr()">
719
sets the pointer to the <code>ParticleDataEntry</code> object of the
720
particle, based on its current <code>id</code> code.
726
<code><aloc href="EventRecord">Event</aloc></code>
727
class also contains a few methods defined for individual particles,
728
but these may require some search in the event record and therefore
729
cannot be defined as <code>Particle</code> methods.
732
Currently there is no information on polarization states.
736
<!-- Copyright (C) 2012 Torbjorn Sjostrand -->
added
removed
xmldoc/ParticleProperties.xml
