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Java > Open Source Codes > JSci > physics > particles > PiMinus


1 package JSci.physics.particles;
2
3 import JSci.physics.quantum.QuantumParticle;
4
5 /**
6 * A class representing pi-.
7 * @version 1.5
8 * @author Mark Hale
9 */
10 public final class PiMinus extends AntiPion {
11         /**
12         * Constructs a pi-.
13         */
14         public PiMinus() {}
15         /**
16         * Returns the rest mass (MeV).
17         * @return 139.57018
18         */
19         public double restMass() {return 139.57018;}
20         /**
21         * Returns the electric charge.
22         * @return -1
23         */
24         public int charge() {return -1;}
25         /**
26         * Returns the number of 1/2 units of the z-component of isospin.
27         * @return -2
28         */
29         public int isospinZ() {return -2;}
30         /**
31         * Returns the quark composition.
32         */
33         public QuantumParticle[] quarks() {
34                 QuantumParticle comp[]={new AntiUp(),new Down()};
35                 return comp;
36         }
37         /**
38         * Returns the antiparticle of this particle.
39         */
40         public QuantumParticle anti() {
41                 return new PiPlus();
42         }
43         /**
44         * Returns true if qp is the antiparticle.
45         */
46         public boolean isAnti(QuantumParticle qp) {
47                 return (qp!=null) && (qp instanceof PiPlus);
48         }
49         /**
50         * Returns a string representing this class.
51         */
52         public String JavaDoc toString() {
53                 return new String JavaDoc("Pi-");
54         }
55 }
56
57
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