Heat-sealable paper and packaging bag

A heat-sealable paper comprising:

• a paper substrate;
• and
• at least one heat-sealable layer formed on at least one surface of the paper substrate, wherein
• the paper substrate comprises raw material pulp containing softwood pulp as a main component and a dry paper strength additive,
• the heat-sealable layer comprises a water-dispersible resin binder and a lubricant,
• the water-dispersible resin binder comprises at least one selected from the group consisting of an ethylene-(meth)acrylic acid copolymer and a styrene/butadiene copolymer, in which,
• when the water-dispersible resin binder comprises the ethylene-(meth)acrylic acid copolymer, the lubricant comprises carnauba wax, or
• when the water-dispersible resin binder comprises the styrene/butadiene copolymer, the lubricant comprises paraffin wax, and
• in the heat-sealable paper, when a tensile energy absorption in a longitudinal direction of the heat-sealable paper as measured in accordance with JIS P 8113:2006 is defined as X1a, a tensile energy absorption in a transverse direction of the heat-sealable paper as measured in accordance with JIS P 8113:2006 is defined as Y1a, a tensile energy absorption index in the longitudinal direction as measured in accordance with JIS P 8113:2006 is defined as X2a, and a tensile energy absorption index in the transverse direction as measured in accordance with JIS P 8113:2006 is defined as Y2a, a geometric mean of X1a and Y1a is 120 J/m2 or more, a ratio of X1a to Y1a (X1a/Y1a) is 0.5 or more and 2.0 or less, and a geometric mean of X2a and Y2a is 2.0 J/g or more.