Re: Extended particle list in TGeant3

From: Yuri Kharlov <yuri.kharlov_at_ihep.ru>
Date: Fri, 07 Jan 2005 12:12:08 +0300

Dear Rene and Adreas,

Please find attached tha patch to TGeant3.cxx (cvs version 1.39) what I propose to modify concerning quarkonia decays. Apply it by "patch TGeant3.cxx TGeant3.cxx.diff".
Could you please look if it does not contradict to external decayers (now all quarkonia will decay into mu+mu-)? Probably, external decayer users will need to declare J/psi as stable. If you feel it not convenient, let us not apply my changes and let users declare needed decays manually.

Best regards,
Yuri.

Rene Brun wrote:

>Andreas, Yuri,
>
>Could one of you send me the fix for this problem?
>
>Rene
>
>Andreas Morsch wrote:
>
>
>>Dear Yuri,
>>I agree, if you un-comment the code it will be wrong.
>>The particle id's in comment have not evolved with the compiled code.
>>So if you need to uncomment this part you should perform you proposed
>>corrections.
>>
>>Best regards - Andreas.
>>
>>
>>
>>>Dear Andreas,
>>>
>>>I agree that external decayers for J/psi and other vector mesons is more
>>>correct as simple isotropic decay. Unfortunately, not all applications
>>>have their external decayer yet (besides aliroot).
>>>
>>>As to decay definition in TGeant3.cxx v.1.34, in this and even in the
>>>head version, some misleading comments about J/psi and Upsilon decay do
>>>present, but actually they decay non-existing particles 113 and 114 into
>>>mu+mu-. It is this code which confused me.
>>>
>>>Best regards,
>>>Yuri.
>>>
>>>
>
>
>

• TGeant3.cxx Fri Jan 7 09:57:11 2005 +++ TGeant3.cxx.yk Fri Jan 7 09:48:33 2005 @@ -1445,19 +1445,19 @@ Gspart(fNG3Particles++, "Lambda_b bar", 3, 5.624, -0., 1.24e-12); fPDGCode[fNPDGCodes++]=-5122; //65 = Lambda_b bar
  • Gspart(fNG3Particles++, "J/Psi", 3, 3.09688, 0., 0.); + Gspart(fNG3Particles++, "J/Psi", 3, 3.09688, 0., 7.6e-21); fPDGCode[fNPDGCodes++]=443; // 66 = J/Psi
  • Gspart(fNG3Particles++, "Psi Prime", 3, 3.686, 0., 0.); + Gspart(fNG3Particles++, "Psi Prime", 3, 3.686, 0., 2.2e-22); fPDGCode[fNPDGCodes++]=20443; // 67 = Psi prime
  • Gspart(fNG3Particles++, "Upsilon(1S)", 3, 9.46037, 0., 0.); + Gspart(fNG3Particles++, "Upsilon(1S)", 3, 9.46037, 0., 1.3e-20); fPDGCode[fNPDGCodes++]=553; // 68 = Upsilon(1S)
  • Gspart(fNG3Particles++, "Upsilon(2S)", 3, 10.0233, 0., 0.); + Gspart(fNG3Particles++, "Upsilon(2S)", 3, 10.0233, 0., 1.5e-20); fPDGCode[fNPDGCodes++]=20553; // 69 = Upsilon(2S)
  • Gspart(fNG3Particles++, "Upsilon(3S)", 3, 10.3553, 0., 0.); + Gspart(fNG3Particles++, "Upsilon(3S)", 3, 10.3553, 0., 2.5e-20); fPDGCode[fNPDGCodes++]=30553; // 70 = Upsilon(3S)

   Gspart(fNG3Particles++, "Anti Neutrino (e)", 3, 0., 0., 1.e20); @@ -1597,25 +1597,29 @@

     bratio[0] = 100.;
     mode[0] = 809;
     Gsdk(ipa, bratio, mode);

- /*
 // --- jpsi ---

     for (kz = 0; kz < 6; ++kz) {
 	bratio[kz] = 0.;
 	mode[kz] = 0;
     }

- ipa = 113;
+ ipa = 66;

     bratio[0] = 50.;
     bratio[1] = 50.;
     mode[0] = 506;
     mode[1] = 605;
     Gsdk(ipa, bratio, mode);

-// --- upsilon ---
- ipa = 114;
+// --- Psi Prime ---
+ ipa = 67;

     Gsdk(ipa, bratio, mode);
-// --- phi ---
- ipa = 115;

+// --- Upsilon (1S)---
+    ipa = 68;
+    Gsdk(ipa, bratio, mode);
+// --- Upsilon (2S)---
+    ipa = 69;
+    Gsdk(ipa, bratio, mode);
+// --- Upsilon (3S)---
+    ipa = 70;
     Gsdk(ipa, bratio, mode);

- */
 //

     AddParticlesToPdgDataBase();
 } Received on Fri Jan 07 2005 - 10:12:14 MET