01: package JSci.physics.particles;
02:
03: import JSci.physics.quantum.QuantumParticle;
04:
05: /**
06: * A class representing pi+.
07: * @version 1.5
08: * @author Mark Hale
09: */
10: public final class PiPlus extends Pion {
11: /**
12: * Constructs a pi+.
13: */
14: public PiPlus() {
15: }
16:
17: /**
18: * Returns the rest mass (MeV).
19: * @return 139.57018
20: */
21: public double restMass() {
22: return 139.57018;
23: }
24:
25: /**
26: * Returns the electric charge.
27: * @return 1
28: */
29: public int charge() {
30: return 1;
31: }
32:
33: /**
34: * Returns the number of 1/2 units of the z-component of isospin.
35: * @return 2
36: */
37: public int isospinZ() {
38: return 2;
39: }
40:
41: /**
42: * Returns the quark composition.
43: */
44: public QuantumParticle[] quarks() {
45: QuantumParticle comp[] = { new Up(), new AntiDown() };
46: return comp;
47: }
48:
49: /**
50: * Returns the antiparticle of this particle.
51: */
52: public QuantumParticle anti() {
53: return new PiMinus();
54: }
55:
56: /**
57: * Returns true if qp is the antiparticle.
58: */
59: public boolean isAnti(QuantumParticle qp) {
60: return (qp != null) && (qp instanceof PiMinus);
61: }
62:
63: /**
64: * Returns a string representing this class.
65: */
66: public String toString() {
67: return new String("Pi+");
68: }
69: }
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