Draft: [trigEGam] Integration beteween mongroups and TrigEgammaMonitoring

This MR is to include mongroups inside the TrigEgammaMonitoring framework.

• A method was implemented in the TrigEgammaMonitCategoryMT reading, for now, the mongoups from JSON local file produced by a ART test.
• At this moment, only the primary chains was configured, and then, called inside the TrigEgammaMonitorConfigMT.py file .
• In a next MR, we will include a logic to route chains to shifter and expert folders automatically, according to their respective mongroups.

JIRA Ticket: ATR-25841 .

ping: @safarzad , @cjmeyer , @fernando , @kyjones and @jlieberm

Generators/Pythia8_i/src/UserHooks/WZPolarization.cxx

+/*
+  Copyright (C) 2002-2022 CERN for the benefit of the ATLAS collaboration
+*/
+#include "Pythia8_i/UserHooksFactory.h"
+#include "UserHooksUtils.h"
+#include "UserSetting.h"
+#include "Pythia8/PhaseSpace.h"
+
+namespace Pythia8 {
+
+
+  /// Convert all resonant W/Z boson decays to the angular distribution of a pure polarisation state
+  //
+  // Polarisation state set via Main:spareMode1 = 0,1,2,3,4
+  // for isotropic, longitudinal, transverse, and trans+, trans-.
+  struct WZPolarization : public UserHooks {
+
+    WZPolarization() : m_polmode("WZPolarization:mode", 1) { }
+
+    bool canVetoResonanceDecays() { return true; }
+
+    bool doVetoResonanceDecays(Event& process) {
+      const int polmode = m_polmode(settingsPtr);
+
+      for (int i = 1; i < process.size(); ++i) {
+        // Select vector bosons
+        Particle& v = process[i];
+        if (v.id() != 23 && v.idAbs() != 24) continue;
+        const Vec4 pv = v.p();
+
+        // Find W/Z daughter particles
+        Particle& d1 = process[v.daughter1()];
+        Particle& d2 = process[v.daughter2()];
+
+        // Get daughter momenta in the boson rest frame
+        Vec4 pd1 = d1.p();
+        Vec4 pd2 = d2.p();
+        pd1.bstback(pv);
+        pd2.bstback(pv);
+
+        // Randomly reorient and rejection-sample decay configuration
+        // (done inline here, rather than reboosting to the W/Z frame on each decay-hook iteration)
+        while (true) {
+
+          // Random reorientation
+          const double dtheta = std::acos(2*rand01() - 1);
+          const double dphi = 2*M_PI*rand01();
+          pd1.rot(dtheta, dphi);
+          pd2.rot(dtheta, dphi);
+
+          // Angle w.r.t. W/Z flight direction, in rest-frame
+          const double th = theta(pv, pd1);
+
+          // Accept/reject the angle according to the polarisation being modelled
+          if (polmode == 0) { // Isotropic
+            break; // it's already been isotropically randomised
+          } else if (polmode == 1) { // Longitudinal
+            if (rand01() < sqr(std::sin(th))) break;
+          } else if (polmode == 2) { // Trans-sum
+            if (rand01() < (1 + sqr(std::cos(th)))/2) break;
+          } else if (polmode == 3) { // Trans+
+            if (rand01() < sqr(1 + std::cos(th))/4) break;
+          } else if (polmode == 4) { // Trans-
+            if (rand01() < sqr(1 - std::cos(th))/4) break;
+          }
+        }
+
+        // Boost the vectors back to the lab frame
+        pd1.bst(pv); d1.p(pd1);
+        pd2.bst(pv); d2.p(pd2);
+
+      }
+
+      return false;
+    }
+
+    double sqr(double x) { return x*x; }
+
+    double rand01() { return rndmPtr->flat(); }
+
+    Pythia8_UserHooks::UserSetting<int> m_polmode;
+
+  };
+
+
+  Pythia8_UserHooks::UserHooksFactory::Creator<Pythia8::WZPolarization> WZPOL("WZPolarization");
+
+}