is better to write scientific paper alone or with participants ?

The question can be interpreted in two ways, 1. [better to "write" on your own about the results of a team effort]; or 2. ["conduct and write" research on your own] (i.e. is it better to do research on a topic that is smaller but manageable by a single researcher so that objectives and methods are defined by one person only). I will answer according to both interpretations below.

1. [writing on your own about a team effort] 
It really depends on i) how good / experienced / confident one is with writing. Typically a junior researcher can really benefit from close mentorship in summing up the results and scientific claims at the beginning of their career. My advice for instance to Ph.D. students is not to delegate writing to more senior authors, as this is a crucial skill that must be built, trained and maintained throughout the academic career. Of course, a more experienced "writer" taking the solo-initiative would indeed speed up the process, therefore depending on how quickly the team needs the results published, they can manage the writing strategy and/or core-team.
In all cases, writing on your own about a team effort will nevertheless require all other research contributors to be listed as authors and to review and approve the manuscript before it is submitted. This is in fact quite common, and the CRediT taxonomy for author contributions can be used to explicitly identify one of the authors as the sole author credited for writing the original paper. The exact wording for this in the author contributions section of a manuscript is "Writing - original draft". This decision (i.e. at which stage other coauthors come in with their revision/writing) should not affect the research impact of the paper.

2. [conducting and writing research on your own] 
This is somehow trickier. The immediate answer would be that collaborative research is by definition more impactful. By involving a team of individuals, methods, scopes, applications, etc. can be significantly broadened to achieve wider reach and readership. If we, instead, think about impact to one's career, being an author buried in the midst of several other authors in a collaborative research paper might be perceived as less prominent in one's track record, compared to authoring a single-author research paper. However, it is unlikely that a junior researcher can single-handedly conceive, execute and publish research. Single author papers rather indicate the work of experienced researchers summing up their unique perspectives and e.g. identify future trends. Having said this, there can be exceptions.

Scientific research has graduated to a level that no scientific project can be properly done unitarily nowadays; scientific research is now done collaboratively. Hence, scientific reports are better done jointly by the team that carried out the research project.

Actually I think that the answer relys on the environment of your connections suppose if you have done the hard work in any experiment or in any research but as you will further go towards the goal you need an assistance like during playing football for goal we have to pass that ball to some one who have the experience of passing the ball either towards the goal or to pass some one else... similarly the experiments work if you done the whole work still you need the assistance of some one who will improve your skills/suggestions which makes bonding and trust and enhances the paper quality, hence its better to write the paper with participants rather than alone. 

writing the original draft alone is better cause its you who had done it. after that you can show it to trusted people to review it and mark possible problems to enhance it. fewer participants shows how much you are good in your field when people read your paper. 

With Participants. Especially with international consortium. 
For the authors, it will boost the citation for the manuscript.
For the consortium, it can further showcase their involvement and contribution in the aim, hence attract more donations. These could further increase funding and grant for the authors to apply. 
For the research institute or Uni, it is a excellent marketing tools in attract more talent to join the team. As a return, the authors will be introduce to the community, hence more network and communication with the talents.
It is a win-win approach.