Jyunana-banme no Higgs Ijigen no Wakaki Ou (Volume)

is the first volume of the Jyunana-banme no Higgs light novel series, written by Ryu Hirosaki and Illustrated by Kihiro Yuzuki. It was released under the Dengeki Bunko Imprint in December 2014.

Synopsis
Boys and girls found due to amnesia in the particle physics research facility. The two were named Taro Yukawa and Hanako, and decided to live as siblings.

── Two years have passed since then.

A silver-haired beautiful girl who is also protected by amnesia appears in front of the two who celebrated their 14th birthday. The girl, who calls herself a neutrino, called Taro the Higgs and said, "You are the king of another dimension and my fiancée." Then, Taro and his friends, who visited the research facility to find out the true identity of neutrinos, approach their past.

At that time, an adversary of another dimension attacks Taro and others ──! (source: Dengeki Bunko Official Website - Translated)