baɪ kˈɑːntɹæst, ɐ fˈoʊtɑːn ɪz nˈuːtɹəl ænd ˌɪntɚɹˈækts ɪlˌɛktɹoʊmɐɡnˈɛɾɪkli, sˌoʊ ɪt dᵻpˈɑːzɪts ɪts ˈɛnɚdʒi ɪnðə kˌæloːɹˈɪmᵻɾɚ wɪðˌaʊt lˈiːvɪŋ ɐ tɹˈæk.
By contrast, a photon is neutral and interacts electromagnetically, so it deposits its energy in the calorimeter without leaving a track.