This is the declaration of the String class.
The String describes both open of closed string. Given one end point particle of the string, String(cPPtr ) uses the colour-connection to build up the full string representation.
The string-regions are described by StringRegion objects. They are created dynamically when needed in the fragmentation process. by the getStringRegion method. When created for the first time, a StringRegion is stored in a StringRegionMap according to the (j,k) indices of the region light-cone momentum pair (p+(j) , p-(k) ) [p_plus(j), p_minus(k)].
- Conventions for String construction :
- The plus, minus conventions for the light-cone momenta and
X fractions :
The PDPtr sent to to the string constructor defines the
rightmost endpoint of the string in the momentum space
representation. Then Plus (Minus) denotes the direction toward
this rightmost (leftmost) endpoint [1].
- The Forward (fwd), Backward (bwd) conventions :
String provides interfaces to access variables that depend
on the orientation chosen to performe a step in the fragmentation
procedure.
If the step is taken from the right of the plane representation
then a fwd() (bwd()) interface to such a variable returns its
Plus (Minus) component, while
if the step is taken from the left then a fwd() (bwd()) interface
returns its Minus (Plus) component.
Warning :
No consistency checks are made by the String.
It is the responsibility of the client using the String class to
send the correct end point to the string constructor.
[1]
T. Sjöstrand, Nucl. Phys.B248(1984)469
CLASS
String