File Hit.hpp¶
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namespace ActsFatras
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class Hit
- #include <ActsFatras/EventData/Hit.hpp>
A simulation hit on a surface.
This is the undigitized, truth hit, i.e. just a recording of the particle state at the surface intersection. Since Fatras is surface-based, the hit position is always constrained to a surface. Depending on the simulated interactions the momentum state before and after might differ and is thus stored as two separate four-vectors.
Public Types
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using Scalar = Acts::ActsScalar
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using Vector3 = Acts::ActsVector<3>
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using Vector4 = Acts::ActsVector<4>
Public Functions
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Hit() = default
Construct default hit with (mostly) invalid information.
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inline Hit(Acts::GeometryIdentifier geometryId, Barcode particleId, const Vector4 &pos4, const Vector4 &before4, const Vector4 &after4, int32_t index_ = -1)
Construct from four-position and four-momenta.
All quantities are given in the global coordinate system. It is the users responsibility to ensure that the position correspond to a position on the given surface.
- Parameters
geometryId – Geometry identifier of the surface
particleId – Particle identifier of the particle that created the hit
pos4 – Particle space-time four-vector on the surface
before4 – Particle four-momentum before the interaction
after4 – Particle four-momentum after the interaction
index_ – Hit index along the particle trajectory
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Hit(const Hit&) = default
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Hit(Hit&&) = default
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inline Scalar depositedEnergy() const
Energy deposited by the hit.
- Return values
positive – if the particle lost energy when it passed the surface
negative – if magic was involved
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inline const Vector4 &fourPosition() const
Space-time position four-vector.
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inline constexpr Acts::GeometryIdentifier geometryId() const
Geometry identifier of the hit surface.
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inline constexpr int32_t index() const
Hit index along the particle trajectory.
- Return values
negative – if the hit index is undefined.
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inline const Vector4 &momentum4After() const
Particle four-momentum after the hit.
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inline const Vector4 &momentum4Before() const
Particle four-momentum before the hit.
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inline constexpr Barcode particleId() const
Particle identifier of the particle that generated the hit.
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inline auto position() const
Three-position, i.e. spatial coordinates without the time.
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inline Scalar time() const
Time coordinate.
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inline Vector3 unitDirection() const
Average normalized particle direction vector through the surface.
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inline Vector3 unitDirectionAfter() const
Normalized particle direction vector the hit.
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inline Vector3 unitDirectionBefore() const
Normalized particle direction vector before the hit.
Private Members
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Acts::GeometryIdentifier m_geometryId¶
Identifier of the surface.
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int32_t m_index = -1¶
Index of the hit along the particle trajectory.
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using Scalar = Acts::ActsScalar
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class Hit