Generalized photoproduction specializations for pseudoscalars & vectors

arudei-dev · arudei-dev · commit c3dad13f96c8 · 2021-04-29T17:00:17.000+07:00
- Refactored XchBase from xch_base into base (and specialized the pseudoscalar &amp; vector version under ::kind module);
- Extracted the spin-average | M |^2 calculation for pseudoscalar and vector particles.
diff --git a/src/scattering/photo22.rs b/src/scattering/photo22.rs
@@ -3,11 +3,11 @@
 use super::*;
 
 pub mod base;
+pub mod kind;
 pub mod rx_data;
 pub mod cross_section;
-pub mod xch_base;
 
 pub use base::*;
+pub use kind::*;
 pub use rx_data::*;
-pub use cross_section::*;
-pub use xch_base::*;
+pub use cross_section::*;
diff --git a/src/scattering/photo22/base.rs b/src/scattering/photo22/base.rs
@@ -5,4 +5,10 @@ pub trait PhotoproductionBase {
     fn get_reaction_data(&self) -> &ReactionData;
 
     fn calc_amplitude_avgsq(&self) -> Real;
+}
+
+pub trait XchBase {
+  fn get_xch_mass(&self, rx: &ReactionData) -> Real;
+
+  fn calc_form_factor(&self, rx: &ReactionData) -> Real;
 }
diff --git a/src/scattering/photo22/kind.rs b/src/scattering/photo22/kind.rs
@@ -0,0 +1,4 @@
+use super::*;
+
+pub mod pseudoscalar;
+pub mod vector;
diff --git a/src/scattering/photo22/kind/pseudoscalar.rs b/src/scattering/photo22/kind/pseudoscalar.rs
@@ -0,0 +1,56 @@
+use super::*;
+use crate::math::number::*;
+use crate::quantum::{*, relativistic::*};
+
+
+pub trait XchBasePseudoscalar : XchBase {
+    fn calc_invariant_amplitude(
+        &self,
+        rx: &ReactionData,
+        h_photon: Helicity,
+    ) -> StateMatrix;
+}
+
+pub struct QuantumStatesIters {
+    h_photon: Vec<Helicity>,
+    sp_inc_b: Vec<Spin>,
+    sp_out_d: Vec<Spin>,
+}
+
+pub fn calc_ampl_avgsq(
+    rx: &ReactionData, 
+    xchs: &Vec<Box<dyn XchBasePseudoscalar>>, 
+    iter_states: QuantumStatesIters, 
+    spin_avg: Real
+) -> Real {
+    if rx.energy == 0. { return 0. }
+
+    let ampl_sq = |h1: Helicity, s1: Spin, s2: Spin| -> Real {
+        let mut sum = Complex::zero();
+
+        let u: &StateVector     = &dirac_spinor(&rx.particles.inc_b, s1);
+        let u_bar: &StateVector = &dirac_adjoint(&dirac_spinor(&rx.particles.out_d, s2));
+
+        for xch in xchs {
+            let m = xch.calc_invariant_amplitude(rx, h1);
+
+            // < f | M | i >
+            sum += u_bar * m * u;
+        }
+
+        return sum.norm_sq();
+    };
+
+    let mut sum = 0.;
+
+    // TODO: Parallelization and iter zip.
+    for h_photon in &iter_states.h_photon {
+        for s_inc_b in &iter_states.sp_inc_b {
+            for s_out_d in &iter_states.sp_out_d {
+                sum += ampl_sq(*h_photon, *s_inc_b, *s_out_d);
+            }
+        }
+    }
+
+    return sum / spin_avg;
+}
diff --git a/src/scattering/photo22/kind/vector.rs b/src/scattering/photo22/kind/vector.rs
@@ -0,0 +1,62 @@
+use super::*;
+use crate::math::number::*;
+use crate::quantum::{*, relativistic::*};
+
+
+pub trait XchBaseVector : XchBase {
+    fn calc_invariant_amplitude(
+        &self,
+        rx: &ReactionData,
+        h_photon: Helicity,
+        h_vector: Helicity,
+    ) -> StateMatrix;
+}
+
+pub struct QuantumStatesIters {
+    h_photon: Vec<Helicity>,
+    h_out_c:  Vec<Helicity>,
+    sp_inc_b: Vec<Spin>,
+    sp_out_d: Vec<Spin>,
+}
+
+pub fn calc_ampl_avgsq(
+    rx: &ReactionData, 
+    xchs: &Vec<Box<dyn XchBaseVector>>, 
+    iter_states: QuantumStatesIters, 
+    spin_avg: Real
+) -> Real {
+
+    if rx.energy == 0. { return 0. }
+
+    let ampl_sq = |h1: Helicity, s1: Spin, h2: Helicity, s2: Spin| -> Real {
+        let mut sum = Complex::zero();
+
+        let u: &StateVector     = &dirac_spinor(&rx.particles.inc_b, s1);
+        let u_bar: &StateVector = &dirac_adjoint(&dirac_spinor(&rx.particles.out_d, s2));
+
+        for xch in xchs {
+            let m = xch.calc_invariant_amplitude(rx, h1, h2);
+
+            // < f | M | i >
+            sum += u_bar * m * u;
+        }
+
+        // | < f | M | i >_1 + < f | M | i >_2 + ... < f | M | i >_n |^2
+        return sum.norm_sq();
+    };
+
+    let mut sum = 0.;
+
+    // TODO: Parallelization and iter zip.
+    for h_photon in &iter_states.h_photon {
+        for s_inc_b in &iter_states.sp_inc_b {
+            for h_out_c in &iter_states.h_out_c {
+                for s_out_d in &iter_states.sp_out_d {
+                    sum += ampl_sq(*h_photon, *s_inc_b, *h_out_c, *s_out_d);
+                }
+            }
+        }
+    }
+
+    return sum / spin_avg;
+}
diff --git a/src/scattering/photo22/xch_base.rs b/src/scattering/photo22/xch_base.rs
