Make the particle isospin property return a float

particle/data/mass_width_2008_ext.fwf

@@ -73,10 +73,11 @@
 * See the full table for descriptions of fields.
 *
 *MASS(MeV)    ,Err+   ,Err-   ,WIDTH(MeV)  ,Err+   ,Err-   ,I  ,G,J   ,P,C,A,PDG-MC ,Chrg,R,S,Name             ,Quarks
-0             ,0      ,0      ,0           ,0      ,0      ,0  , ,1/2 , , ,F,     12,   0, ,D,nu(e)            ,
-0             ,0      ,0      ,0           ,0      ,0      ,0  , ,1/2 , , ,F,     14,   0, ,D,nu(mu)           ,
-0             ,0      ,0      ,0           ,0      ,0      ,0  , ,1/2 , , ,F,     16,   0, ,D,nu(tau)          ,
-0             ,0      ,0      ,0           ,0      ,0      ,0  , ,1   ,-, , ,     21,   0, ,R,g                ,
+0             ,0      ,0      ,0           ,0      ,0      ,   , ,1/2 , , ,F,     12,   0, ,D,nu(e)            ,
+0             ,0      ,0      ,0           ,0      ,0      ,   , ,1/2 , , ,F,     14,   0, ,D,nu(mu)           ,
+0             ,0      ,0      ,0           ,0      ,0      ,   , ,1/2 , , ,F,     16,   0, ,D,nu(tau)          ,
+0             ,0      ,0      ,0           ,0      ,0      ,   , ,1   ,-, , ,     21,   0, ,R,g                ,
+0             ,0      ,0      ,0           ,0      ,0      ,   , ,1   ,-,-, ,     22,   0, ,R,gamma            ,
 0             ,0      ,0      ,0           ,0      ,0      ,   , ,0   , , , ,     25,   0, ,R,H                ,
 0             ,0      ,0      ,0           ,0      ,0      ,1  ,-,1   ,-, ,B,9000213,   +, ,R,pi(1)(1400)      ,Maybe non-qQ
 0             ,0      ,0      ,0           ,0      ,0      ,1  ,-,1   ,-,+, ,9000113,   0, ,R,pi(1)(1400)      ,Maybe non-qQ

particle/data/particle2019.csv

@@ -13,18 +13,18 @@ ID,Mass,MassUpper,MassLower,Width,WidthUpper,WidthLower,I,G,P,C,Anti,Charge,Rank
 -6,173100,900,900,1420,190,150,0,5,1,5,1,-2,0,0,t,T,\bar{t}
 11,0.5109989461,3.1e-09,3.1e-09,0,0,0,,5,5,5,2,-3,0,0,e,,e^{-}
 -11,0.5109989461,3.1e-09,3.1e-09,0,0,0,,5,5,5,2,3,0,0,e,,e^{+}
-12,0,0,0,0,0,0,0,5,5,5,1,0,0,1,nu(e),,\nu_{e}
--12,0,0,0,0,0,0,0,5,5,5,1,0,0,1,nu(e),,\bar{\nu}_{e}
+12,0,0,0,0,0,0,,5,5,5,1,0,0,1,nu(e),,\nu_{e}
+-12,0,0,0,0,0,0,,5,5,5,1,0,0,1,nu(e),,\bar{\nu}_{e}
 13,105.6583745,2.4e-06,2.4e-06,2.9959847e-16,3e-22,3e-22,,5,5,5,2,-3,0,0,mu,,\mu^{-}
 -13,105.6583745,2.4e-06,2.4e-06,2.9959847e-16,3e-22,3e-22,,5,5,5,2,3,0,0,mu,,\mu^{+}
-14,0,0,0,0,0,0,0,5,5,5,1,0,0,1,nu(mu),,\nu_{\mu}
--14,0,0,0,0,0,0,0,5,5,5,1,0,0,1,nu(mu),,\bar{\nu}_{\mu}
+14,0,0,0,0,0,0,,5,5,5,1,0,0,1,nu(mu),,\nu_{\mu}
+-14,0,0,0,0,0,0,,5,5,5,1,0,0,1,nu(mu),,\bar{\nu}_{\mu}
 15,1776.86,0.12,0.12,2.267e-09,4e-12,4e-12,,5,5,5,2,-3,0,0,tau,,\tau^{-}
 -15,1776.86,0.12,0.12,2.267e-09,4e-12,4e-12,,5,5,5,2,3,0,0,tau,,\tau^{+}
-16,0,0,0,0,0,0,0,5,5,5,1,0,0,1,nu(tau),,\nu_{\tau}
--16,0,0,0,0,0,0,0,5,5,5,1,0,0,1,nu(tau),,\bar{\nu}_{\tau}
-21,0,0,0,0,0,0,0,5,-1,5,0,0,0,0,g,,g
-22,0,0,0,0,0,0,<2,5,-1,-1,0,0,0,0,gamma,,\gamma
+16,0,0,0,0,0,0,,5,5,5,1,0,0,1,nu(tau),,\nu_{\tau}
+-16,0,0,0,0,0,0,,5,5,5,1,0,0,1,nu(tau),,\bar{\nu}_{\tau}
+21,0,0,0,0,0,0,,5,-1,5,0,0,0,0,g,,g
+22,0,0,0,0,0,0,,5,-1,-1,0,0,0,0,gamma,,\gamma
 23,91187.6,2.1,2.1,2495.2,2.3,2.3,,5,5,5,0,0,0,0,Z,,Z^{0}
 24,80379,12,12,2085,42,42,,5,5,5,2,3,0,0,W,,W^{+}
 -24,80379,12,12,2085,42,42,,5,5,5,2,-3,0,0,W,,W^{-}

particle/particle/particle.py

@@ -48,6 +48,16 @@ class InvalidParticle(RuntimeError):
     pass
 
 
+def _isospin_converter(isospin):
+    vals = {
+        "0": 0.,
+        "1/2": 0.5,
+        "1": 1.0,
+        "3/2": 1.5
+    }
+    return vals.get(isospin, None)
+
+
 @total_ordering
 @attr.s(slots=True, cmp=False, repr=False)
 class Particle(object):
@@ -156,7 +166,7 @@ class Particle(object):
     width_upper = attr.ib(-1, converter=lambda v: None if v < 0 else v)
     width_lower = attr.ib(-1, converter=lambda v: None if v < 0 else v)
     _three_charge = attr.ib(Charge.u, converter=Charge)  # charge * 3
-    I = attr.ib(None)
+    I = attr.ib(None, converter=_isospin_converter)
     # J = attr.ib(None)  # Total angular momentum
     G = attr.ib(Parity.u, converter=Parity)  # Parity: '', +, -, or ?
     P = attr.ib(Parity.u, converter=Parity)  # Space parity
@@ -537,7 +547,7 @@ def _charge_in_name(self):
         if self.pdgid in (9000113, 9010113): return True  # special particles not yet well-known in the 2018 table
         # Lambda baryons
         if (self.pdgid.is_baryon
-            and _digit(self.pdgid, Location.Nq2) == 1 and self.I == '0'  # 1st check alone is not sufficient to filter out lowest-ground Sigma's
+            and _digit(self.pdgid, Location.Nq2) == 1 and self.I == 0.  # 1st check alone is not sufficient to filter out lowest-ground Sigma's
             and self.pdgid.has_strange
             and not (self.pdgid.has_charm or self.pdgid.has_bottom or self.pdgid.has_top)
            ):

tests/particle/test_particle.py

@@ -378,6 +378,36 @@ def test_spin_type(pid, stype):
     assert particle.spin_type == stype
 
 
+checklist_isospin = (
+    # Quarks
+    (1, 0.5),        # d
+    # Gauge bosons
+    (22, None),      # photon
+    (23, None),      # Z0
+    # Leptons
+    (11, None),      # e-
+    (-12, None),     # nu(e)_bar
+    # Mesons
+    (211, 1.0),      # pi+
+    (310, 0.5),      # K_S
+    (-421, 0.5),     # D0_bar
+    (333, 0.0),      # phi(1020)
+    (443, 0.0),      # J/psi
+    (521, 0.5),      # B+
+    (531, 0.0),      # Bs
+    # Baryons
+    (2212, 0.5),     # proton
+    (2214, 1.5),     # Delta+
+)
+
+
+@pytest.mark.parametrize("pid,isospin", checklist_isospin)
+def test_isospin(pid, isospin):
+    particle = Particle.from_pdgid(pid)
+
+    assert particle.I == isospin
+
+
 def test_default_particle():
     p = Particle.empty()