There's a boy and a girl around first year high school or at 3rd year middle school

the girls love alien and annoyed the boy about alien this and that

the boy did not believe in alien and tell her to stop being so childish

the next morning at the train station, the girl have this bandage attached at her forehead

the girl told the boy she got abducted by alien, she got operated at her head and she still remember about it

the boy then harshly scold her that she was lying and tell her to stop the nonsense, the girl got mad and approached the boy and yell at her

some arguing, the boy can't take it and shout at her that alien does not exist, and accidently push her from the train tracks

train comes, the girl dies . It then concluded that she dies from accident, they live at country side, at early morning, there's very few people there and no witness on the boy pushing.

the boy feels guilty , blames and hating the alien thing more, at night he saw a flash of light at the sky. He remember before the girl die, she say that she gonna chase the flash of light.

The boy go out at night to take a stroll and want to see what bullshit is that light. He got abducted by alien.

he meet two alien, a young female and a young boy alien. The young boy have this serious and mature looking, while the girl have this emotionless face/attitude. They say their experiment subject has die(the girl).

they told the boy that their race already extinct, and only those two who are the last one alive. they want to copulate to get offsprings but they can't, because their race does'nt have anything called emotion. Because there's no love emotion, no matter how they want to do it, they can't.

The aliens then say they abduct the girl , operate her head and transfer her memory that contains her emotion on the chip and studying it. They then decided it was'nt enough and try to observe the girl living life at earth.

but she die, so then they decided to transfer the experiment to the boy who was the girl love interest. The guy was confused, and the male alien plant the girls memory on the female alien. The female alien then act exactly like the girl before she die.

the male alien then say that it was like "copy" and the girl overwritten the alien girl personality.

They then decided to let the "copy" interact with the boy to study further of human emotions.

of course the boy refused, somewhat the alien girl attached some chip at her forehead and she become the girl and changed 180 deegre, When she took it off, she become emotionless and act no cares. This make the boy mad because they play with human emotions.

but in the end the boy agree by some persuasion.

what manga is this ? i think i read it in 2014 or 2015 year but forgot the title

Is it Sora x Rira - Sorairo no Lila to Okubyou na Boku?

YES TY