Low bias KSLL for D02KSHH low bias line

Added a low-bias selection for KSLL candidates for D02KSHH Low Bias line. Two algorithms are added:

• make_long_pions_from_ks_lowbias that selects rich long pions with
  • IP > 200 µm
  • PIDK < 5
  • PT > 200 MeV
  • P > 1500 MeV
• make_kshort_ll_lowbias() that takes as input the pions from above and has slightly looser cuts than make_kshort_ll to align them with the HLT1 line (D2Kshh see Allen!559 (merged)) being ready to be committed. Also the BPVFDCHI2 cut is removed.

The line builders

• dzero2kspimpipLL_lowbiasline
• dzero2kskmkpLL_lowbiasline
• dzero2kskmpipLL_lowbiasline
• dzero2kskppimLL_lowbiasline
• dstarp2dzeropip_dzero2kspimpipLL_lowbiasline
• dstarp2dzeropip_dzero2kskmkpLL_lowbiasline
• dstarp2dzeropip_dzero2pipkmksLL_lowbiasline
• dstarp2dzeropip_dzero2pimkpksLL_lowbiasline

then take KS candidates from make_kshort_ll_lowbias

Hlt/Hlt2Conf/python/Hlt2Conf/lines/charm/d0_to_kshh.py

@@ -111,14 +111,30 @@ def make_charm_pions_lowbias():
         make_has_rich_long_pions(),
         F.FILTER(
             F.require_all(
-                F.PT > 500 * MeV,
-                F.P > 5 * GeV,
+                F.PT > 400 * MeV,
+                F.P > 1500 * GeV,
                 F.MINIPCUT(IPCut=60 * um, Vertices=make_pvs()),
                 F.PID_K < 0.,
             ), ),
     )
 
 
+def make_long_pions_from_ks_lowbias():
+    """Return maker for pions filtered by thresholds common to LL kshort
+    decay product selections to be used for low bias line. 
+    """
+    return ParticleFilter(
+        make_has_rich_long_pions(),
+        F.FILTER(
+            F.require_all(
+                F.MINIPCUT(IPCut=200. * um, Vertices=make_pvs()),
+                F.PID_K < 5.,
+                F.PT > 200 * MeV,
+                F.P > 1500 * MeV,
+            ), ),
+    )
+
+
 def make_long_pions_from_ks():
     """Return maker for pions filtered by thresholds common to LL kshort
     decay product selections.
@@ -196,6 +212,29 @@ def make_kshort_dd():
     )
 
 
+def make_kshort_ll_lowbias():
+    """Return Kshort with two long pions maker"""
+    return ParticleCombiner(
+        [make_long_pions_from_ks_lowbias(),
+         make_long_pions_from_ks_lowbias()],
+        DecayDescriptor="KS0 -> pi- pi+",
+        name='Charm_D0ToKshh_KS0_LL_LowBias_{hash}',
+        CombinationCut=F.require_all(
+            in_range(435 * MeV, F.MASS, 560 * MeV),
+            F.PT > 200 * MeV,
+            F.P > 2.5 * GeV,
+            F.MAXDOCACUT(150 * um),
+        ),
+        CompositeCut=F.require_all(
+            in_range(455 * MeV, F.MASS, 540 * MeV),
+            F.PT > 250 * MeV,
+            F.P > 3 * GeV,
+            F.CHI2DOF < 9.,
+            F.BPVVDZ(make_pvs()) > 4 * mm,
+        ),
+    )
+
+
 def make_dzeros(particle1,
                 particle2,
                 particle3,
@@ -292,7 +331,7 @@ def dzero2kspimpipDD_line(name='Hlt2Charm_D0ToKsPimPip_DD', prescale=0.1):
 def dzero2kspimpipLL_lowbiasline(name='Hlt2Charm_D0ToKsPimPip_LL_LowBias',
                                  prescale=0.1):
     pions = make_charm_pions_lowbias()
-    kshorts = make_kshort_ll()
+    kshorts = make_kshort_ll_lowbias()
     dzeros = make_dzeros_lowbias(kshorts, pions, pions, "D0 -> KS0 pi- pi+")
     return Hlt2Line(
         name=name,
@@ -342,7 +381,7 @@ def dzero2kskmkpDD_line(name='Hlt2Charm_D0ToKsKmKp_DD', prescale=0.1):
 def dzero2kskmkpLL_lowbiasline(name='Hlt2Charm_D0ToKsKmKp_LL_LowBias',
                                prescale=0.1):
     kaons = make_charm_kaons_lowbias()
-    kshorts = make_kshort_ll()
+    kshorts = make_kshort_ll_lowbias()
     dzeros = make_dzeros_lowbias(kshorts, kaons, kaons, "D0 -> KS0 K- K+")
     return Hlt2Line(
         name=name,
@@ -395,7 +434,7 @@ def dzero2kskmpipLL_lowbiasline(name='Hlt2Charm_D0ToKsKmPip_LL_LowBias',
                                 prescale=0.1):
     pions = make_charm_pions_lowbias()
     kaons = make_charm_kaons_lowbias()
-    kshorts = make_kshort_ll()
+    kshorts = make_kshort_ll_lowbias()
     dzeros = make_dzeros_lowbias(kshorts, kaons, pions, "[D0 -> KS0 K- pi+]cc")
     return Hlt2Line(
         name=name,
@@ -449,7 +488,7 @@ def dzero2kskppimLL_lowbiasline(name='Hlt2Charm_D0ToKsKpPim_LL_LowBias',
                                 prescale=0.1):
     pions = make_charm_pions_lowbias()
     kaons = make_charm_kaons_lowbias()
-    kshorts = make_kshort_ll()
+    kshorts = make_kshort_ll_lowbias()
     dzeros = make_dzeros_lowbias(kshorts, kaons, pions, "[D0 -> KS0 K+ pi-]cc")
     return Hlt2Line(
         name=name,