Limitations of CMB <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>B</mml:mi></mml:math> -mode template delensing

Measurements of the primordial B modes CMB are crucial for testing cosmic inflation. However, gravitational lensing photons contaminates these measurements. Here, authors show, through analytic and numerical work, that simplest method removing this contamination, using a template at gradient level based on lensed E modes, is perhaps unexpectedly, remarkably effective will be very useful in analyzing data, especially detecting low values tensor to scalar ratio.