Polymerizable composition and lithographic printing plate precursor

1. A lithographic printing plate precursor comprising: a support; and a recording layer,

the recording layer containing:

(A) a binder polymer;

(B) a compound having a polymerizable unsaturated group;

(C) a compound which has a triarylsulfonium salt structure and in which the sum of Hammett's constants of all substituents bonded to the aryl skeleton is larger than 0.50,

wherein the compound (C) has a triarylsulfonium cationic structure containing three or more halogen atoms and has an organic anion selected from the group consisting of a sulfonate anion, a benzoylformate anion, a carboxylate anion, a sulfinate anion, a sulfate anion, a polymeric sulfonate anion and a polymeric carboxylate anion; and

(D) a compound having an absorption maximum at 700 to 1200 nm,

wherein the compound (D) is represented by the following formula (a):

 wherein X 1 represents a hydrogen atom, a halogen atom, —NAr 3 2 , X 2 -L 1 or the following group (a-1), X 2 represents an oxygen atom or a sulfur atom, while L 1 represents a hydrocarbon group having 1 to 12 carbon atoms, an aromatic ring having a hetero atom or a hydrocarbon group containing a hetero atom and having 1 to 12 carbon atoms, and Ar 3 represents a substituted or unsubstituted aromatic hydrocarbon group having from 6 to 14 carbon atoms; R 1 and R 2 each independently represents a hydrocarbon group having 1 to 12 carbon atoms; Ar 1 and Ar 2 each independently represents a substituted or unsubstituted aromatic hydrocarbon group; Y 1 and Y 2 each independently represents a sulfur atom or a dialkylmethylene group having 12 or less carbon atoms; R 3 and R 4 each independently represents a substituted or unsubstituted hydrocarbon group having 20 or less carbon atoms; R 5 , R 6 , R 7 and R 8 each independently represents a hydrogen atom or a hydrocarbon group having 12 or less carbon atoms; and Za − represents a counter anion:

wherein Xa − represents a counter anion; and R a represents a hydrogen atom, an alkyl group, an aryl group, a substituted or unsubstituted amino group, or a halogen atom.

2. The lithographic printing plate precursor according to claim 1 , wherein the organic anion is a sulfonate anion.

3. The lithographic printing plate precursor according to claim 1 , wherein the sum of Hammett's constants of all substituents bonded to the aryl skeleton is larger than 0.60.