Jazz Keith Jarrett: ''Standards, Vol. 1.'' Keith Jarrett, piano; Gary Peacock, bass; Jack DeJohnette, drums. (ECM 23793-1) - Keith Jarrett's classical touch lends itself well to this collection of standards. His two-handed approach to piano is nicely complemented by Peacock and DeJohnette, who have just the right ear for the rhythmic displacement and polyphony that Jarrett seems to delight in. The tunes are good ones: ''It Never Entered My Mind,'' ''All the Things You Are,'' ''The Masquerade Is Over,'' and so on. The only klunker is ''God Bless the Child,'' a soft-rock gospel travesty on the Billie Holiday classic, capped by a seemingly endless coda. Also, Jarrett's annoying habit of grunting and singing off-key while he plays is mightily distracting during most of the cuts. Neverthless, the passionate invention of his improvisations make up for these flaws.