Documentation of KWFIT Routines

The general sequence of calls is shown in the simple example to help you get started. More extensive examples are provided elsewhere in the documentation.

Important General Routines

kset_init	Initialize KWFIT (first call to system)
kset_clear	Clear track list (done at beginning of event)
kset_bfield	Set B field information (done at beginning of run)
kset_beam_position	Set beam position and errors (done at beginning of run)
kset_beam_momentum	Set beam 4-momentum (done at beginning of run)
kset_fit_criteria	Sets fit criteria used in KWFIT
kset_default_vtx_errors	Sets default large vertex errors when fitting for unknown vertices

General Information Routines

kget_bfield	Returns B field information
kget_beam_position	Returns beam position and errors
kget_beam_position_cov	Returns beam covariance matrix
kget_beam_momentum	Returns beam 4-momentum
kget_fit_criteria	Returns fit criteria used in all fits
kget_last_fit_info	Returns information about last fit

Routines Which Fill the Track List

kfil_track_create	Create an entry in track list. No information is stored
kfil_track_delete	Delete a track
kfil_track_cd	Load CD track and its errors into track list
kfil_track_cd_all	Load all CD tracks and errors into track list
kfil_track_cd_list	Load a list of CD tracks and errors into track list
kfil_track_knvf	Load secondary vertex and its errors from KNVF into track list
kfil_track_knvf_all	Load all secondary vertices and errors from KNVF into track list
kfil_track_vfnd	Load secondary vertex and its errors from VFND into track list
kfil_track_vfnd_all	Load all secondary vertices and errors from VFND into track list
kfil_track_svtf	Load track segment and its errors from SVTF into track list
kfil_track_svtf_all	Load all track segments and errors from SVTF into track list
kfil_track_ccfc	Load CCFC shower and its errors into track list
kfil_track_ccfc_all	Load all CCFC showers and errors into track list
kfil_track_xbal	Load XBAL shower and its errors into track list
kfil_track_xbal_all	Load all XBAL showers and errors into track list
kfil_track_pi0	Load pizero and its errors into track list
kfil_track_pi0_all	Load all pizeros and errors into track list
kfil_track_qq	Load QQ track into track list
kfil_track_qq_all	Load all QQ tracks into track list
kfil_track_ftmonte	Load FTMONTE track and its errors into track list
kfil_track_ftmonte_all	Load all FTMONTE tracks and errors into track list

Get Track Information

kget_track_number	Returns number of tracks in track list
kget_track_param	Returns track current parameters
kget_track_param0	Returns track unconstrained parameters
kget_track_p4	Returns track 4-momentum
kget_track_covar	Returns track covariance matrix
kget_track_mass	Returns actual mass of track
kget_track_dca_bend	Returns dca of track to point (in bend plane)
kget_track_origin	Returns type of original list track came from (e.g., CD)
kget_track_index	Returns track index in original list (e.g., CD list)
kget_track_is_covar	TRUE if track has a covariance matrix
kget_track_is_position	TRUE if track has position information
kget_track_is_mass_fixed	TRUE if track has a fixed mass
kget_track_err_energy	Returns the energy error of a track
kget_track_err_mass	Returns the mass error of a track
kget_track_err_momentum	Returns the momentum error of a track
kget_track_err_pperp	Returns the pperp error of a track
kget_track_err_phi	Returns the phi error of a track
kget_track_err_theta	Returns the theta error of a track
kget_track_err_dca_bend	Returns error error in dca of track to point (in bend plane)

Set Track Information

kset_track_copy	Copy information from one track to another
kset_track_info	Set most information for a KWFIT track
kset_track_param	Set current track parameters
kset_track_param0	Set unconstrained track parameters
kset_track_covar	Set track covariance matrix for a track
kset_track_mass	Set mass of a track
kset_track_origin	Set the origin of a KWFIT track (i.e., CD list)
kset_track_index	Set index of track in original list (e.g., CD list)
kset_track_is_covar	Set flag indicating whether or not a track has a covariance matrix
kset_track_is_mass_fixed	Set flag indicating whether a track has a fixed or floating mass
kset_track_is_position	Set flag indicating whether or not a track has position information

General Track Utility Routines

ktrk_set_parameters	Set unconstrained parameters to be same as current ones
ktrk_restore_parameters	Restore current track parameters to unconstrained ones
ktrk_add_momentum	Add 4-momentum of one track to another, ignoring position
ktrk_move_arc	Move track & its covariance matrix by a fixed distance
ktrk_move_point	Move track & its covariance matrix to true PCA to a point
ktrk_move_point_bend	Move track & its covariance matrix to PCA in bend plane to a point (CLEO definition of PCA)
ktrk_move_line	Move track & its covariance matrix to a line
ktrk_move_plane	Move track & its covariance matrix to a plane
ktrk_move_zplane	Move track & its covariance matrix to a z position
ktrk_move_radius	Move track & its covariance matrix to a particular radius

Fitting Routines

kfit_update_tracks	Update all tracks from the previous fit
kfit_3momentum	Constrain a KWFIT track to a fixed 3-momentum
kfit_4momentum	Constrain a KWFIT track to a fixed 4-momentum
kfit_mass	Constrain a KWFIT track to a fixed mass
kfit_energy	Constrain a KWFIT track to a fixed energy
kfit_momentum	Constrain a KWFIT track to a fixed total momentum
kfit_vertex_fixed	Constrain a KWFIT track to come from a fixed vertex
kfit_vertex_known	Constrain a KWFIT track to come from a vertex having position & errors
kfit_back_to_back	Constrain 2 KWFIT tracks to be back to back, i.e., dimuon
kfit_back_to_back_cm	Constrain 2 KWFIT tracks to be back to back in CM (unboosted) frame

Vertex Fitting Routines

Note: All vertex fitting routines have an argument which optionally allows the track parameters to be updated. If they are not updated, only the vertex and chi-square information are returned.

kvtx_unknown_approx	Find 3-D vertex using line approximation. No chisquare computed.
kvtx_unknown	Find unknown 3-D vertex
kvtx_known	Find vertex, where initial position and covariance matrix are specified
kvtx_beam	Find vertex, incorporating beam spot information
kvtx_fixed	Force a set of tracks to pass through a single point
kvtx_unknown_2d	Same as kvtx_unknown, except that only r-phi constraint is used
kvtx_known_2d	Same as kvtx_known, except that only r-phi constraint is used
kvtx_fixed_2d	Same as kvtx_fixed, except that only r-phi constraint is used
kvtx_known_lifetime	Find c*tau, where position and cov. matrix of starting point are specified
kvtx_beam_lifetime	Find c*tau using beam spot as starting point
kvtx_fixed_lifetime	Find c*tau, where position of starting point (fixed) is specified
kvtx_two_vertex	Find vertex given a fuzzy prod. pt. and a decay into 1 daughter + neutrals
kvtx_two_vertex_life	Same as kvtx_two_vertex but also fit for lifetime.

Routines Which Build Virtual Particles

kvir_add_nofit	Build particle by adding 4-momenta from several tracks (no constraint)
kvir_vertex_fixed	Build particle constraining tracks to go through fixed vertex
kvir_vertex_known	Build particle constraining tracks to go through known vertex with errors
kvir_vertex_beam	Build particle constraining tracks to go through beam spot
kvir_vertex_unknown	Build particle constraining tracks to go through unknown vertex
kvir_two_vertex	Build particle constraining tracks to the "two-vertex" fit

Miscellaneous Move Routines

Note: All routines which manipulate W tracks use the current B field specified by kset_bfield. None of these routines use the KWFIT track list, they use only information in the argument list.

kmove_wtk_arc	Move a W track a fixed 3-D arc length
kmove_wtk_point	Move a W track to true PCA to the specified point
kmove_wtk_point_bend	Move a W track to PCA in bend plane to the specified point (CLEO definition of PCA)
kmove_wtk_line	Move a W track to PCA to the specified line
kmove_wtk_plane	Move a W track to the specified plane
kmove_wtk_zplane	Move a W track to a particular z value
kmove_wtk_cylinder	Move a W track to the specified cylinder
kmove_wtk_radius	Move a W track to the specified radius

Miscellaneous Utility Routines

Note: All routines which manipulate W tracks use the current B field specified by kset_bfield. None of these routines use the KWFIT track list; they use only information in the argument list.

kutl_boost_from_frame	Boost a W track from a frame moving with a specified velocity
kutl_boost_to_frame	Boost a W track to a frame moving with a specified velocity
kutl_convert_c_to_w	Convert C track (CLEO parameters) to W format
kutl_convert_w_to_c	Convert W track to C track (CLEO parameters)
kutl_convert_ccov_to_wcov	Convert 5x5 C track covariance matrix to 7x7 W covariance matrix
kutl_convert_wcov_to_ccov	Convert 7x7 W track covariance matrix to 5x5 C covariance matrix
kutl_origin_to_current	Returns 3-D arc length from origin to current position on W track
kutl_distance_to_point	Returns the 3-D distance of closest approach from a W track to a point
kutl_dca_bend	Returns the dca from a W track to a point (measured in bend plane)
kutl_distance_line_point	Returns the distance between a 3-D line and a point
kutl_distance_line_line	Returns the distance between two 3-D lines
kutl_intersect_2lines	Finds the intersection point of two 3-D lines
kutl_vertex_approx	Find 3-D vertex using line approximation. No chisquare computed.
kutl_vertex_average	Finds the weighted average of two 3-D vertices and returns chisquare
kutl_vertex_same	Finds the chi-square for two 3-D vertices to be the same
kutl_vertex_err_project	Returns the vertex error along a specified direction
kutl_2vertex_err	Returns the error along line connecting two vertices
ktrk_2vertex_d_over_sigma	Returns D/sigma between a track and vertex along line connecting them
kutl_mass2	Returns the invariant mass of two W tracks
kutl_mass3	Returns the invariant mass of three W tracks
kutl_mass4	Returns the invariant mass of four W tracks
kutl_sum2	Returns the 4-momentum sum of two W tracks
kutl_sum3	Returns the 4-momentum sum of three W tracks
kutl_sum4	Returns the 4-momentum sum of four W tracks