Cap for closing a container, a combination of a cap and a neck

A cap for a container, comprising a side wall extending about an axis and a transversal wall arranged at an end of the side wall, a separation line being provided on the side wall for defining:

• a retaining ring intended to remain anchored to a neck of the container, and
• a closure element which can removably engage the neck, so as to open or close the container;
• wherein the separation line extends about the axis and is circumferentially interrupted so as to leave a joining portion between the retaining ring and the closure element, the cap further having an incision line which extends transversally to the axis between the separation line and a free edge of the retaining ring, so that two connecting bands are defined between the separation line and the incision line, the connecting bands joining the retaining ring to the joining portion, the connecting bands having a radial thickness measured in a radial direction, the connecting bands further having a height measured parallel to the axis, and wherein the ratio between the height and the radial thickness of the connecting bands is greater than, or equal to, 1.4, said ratio being less than, or equal to, 6.5.