The Belle II Membership Management System (B2MMS) it is the exclusive source for Belle II authors, mailing, and voting. All Belle II users must register!

Before you start please:


All users who want to work in the context of the Belle II collaboration must register to the Belle II Membership Management System (B2MMS) to become so-called Belle II users.

According to the by-laws the B2MMS provides different categories. Belle II users are:

  • all official members of the Belle II collaboration usually physicists and PhD students (Belle II members)
  • temporary users such as students,
  • technical staff,
  • visitors who need access to the Belle II collaborative services of non-Belle II institutions (Please choose the inviting institute as home).

Becoming a Belle II user consists of two steps:

  1. The identity of the user must be proven (authentication).
  2. The permission to become a Belle II user must be given (authorization).

Those two steps are delegated to the institution representatives (IR) obeying the local rules, e.g. for underage users.

Users will obtain login credentials (account name / password) ( not an email address) from the DESY registry according to the DESY Requirements for Account Names and Passwords rules to log in to the Belle II collaborative services (B2CS). This is not a KEK account!


The approval workflow and the creation of the credentials takes one workday in CE(S)T. Finally, users will obtain login credentials (account name / password) (not an email address) from the DESY registry. The DESY registry informs the user by email.

The DESY registry will use the names you have given as 'given middle family' and create email addresses such as . Make up your mind if you really want the middle name.

Already a Belle II user?

If you have once been a Belle II user, your record will remain even if your membership expires. Please never ever register again. Status and attributes of your record can be changed at any time; even after expiration or with a new institution. See Instructions for Users (login required).

Already a DESY user?

Users who have an account from former work at DESY even outside Belle II (summer student, other group etc.), please register for Belle II and denote the account name in the account field. It will be reactivated/prepared.

Permanent/staff member?

The registration as ' Physicist - permanent/staff ' requires the approval of the institutional board (IB) on the basis of a formal application to the institutional board. Otherwise the request will be not be processed. Make sure to hand this in via your IR in before-hand! Please check the Belle II contacts web.


Please check your membership record in the Belle II Membership Management System (B2MMS). See docu of the Belle II Membership Management System.

Note: Unique identification of authors is done via the so-called ORCID. Make sure it is registered as described in B2MMS ORCID .

Please never ever register AGAIN or TWICE . A new registration does not extend or reset anything!

If you are unsure whether you have already registered, try to access the B2MMS where you will be asked to log in. To reset a lost password see the FAQ. Note: The password must be renewed after 6 month. You will be informed by email well in advance. Resetting a lost or missed password takes a few days.

Account names (string up to 8 numbers/characters) can not be changed!

If still unsure contact us at .

If your institution has changed, review and change your record according to the Instructions for Users.

If you hold a DESY account from another project which is not enable for Belle II yet, register and denote your already existing account name.

Asian colleagues , please note the naming conventions:

  • first name = given name
  • last name = family name
  • A capital letter first followed by small letters
  • Example: Toru Iijima

Avoid YAHOO, GMAIL etc since they cause problems!!! Please use your email address at your home institution !!!

The account name is a case insensitive string of 4-8 characters . It is NOT an email address. Please chose a decent account name and please remember the initial password which is created for you when filling the portal You will need it when your account is ready. Please denote the DESY Requirements for Account Names and Passwords.

The DESY registry will use the names you have given as 'given middle family' and create email addresses such as Make up your mind if you really want the middle name. The spaces will be transformed to dots!

Example: 'Nino de Angelo' will become '' whereas 'Nino deAngelo' (no middle name) will end up in ''.

The creation of the credentials in the DESY registry will start after the IR has approved the request and will take a workday. Keep in mind: DESY is on CE(S)T. Users will be informed on success and will be asked to login with the initial password and to set a new password.

According to the DESY Password Policy the password expires every 6 month; users will be informed early enough. Please don't ignore the notification. Consider to use a password safe!

Belle II Registration By Invitation

  • In most cases you were invited by your IR and have received an email with a temporary Username / Password which is valid ONLY for the Registration Portal. Firefox works best. Other browser might cause problems due to their security settings. After logging in with the TEMPORARY account/password of the invitation email you will see the page on your right. Note: This account/password are NOT your final credentials. They become invalid after usage for registration!

Belle II Registration with a Grid User Certificate

Next steps

With successfully filling and sending the form via the portal, the user's part is done. The user will see a message such as "Request for Belle2 membership was created. Desired account name: ...". Please remind the account_name and THIS NEW password ! An email will be sent to the representative (IR) of the Belle II institution who must approve the request.

As soon as the registration request is approved by the IR, the user will be added to the B2MMS. The credentials will be created in the DESY registry within the next work day (CE(S)T. The user will be informed by email and will be asked to reset the initial password asap. Please obey the DESY Password Policy.

You are then ready to use all Belle II collaborative services (B2CS) using your account name.

Please also take note of the multi-factor authentication (MFA) which will become default for many services in future. After you have obtained credentials see DESY Multi-Factor Authentication and take action.

REMEMBER the password for you initial login!

Password Recovery

It is important that you keep access to your DESY account, because it is needed for your involvement in the Belle II collaboration. This is in particular the case if you are a group leader, because your group members depend on you.

Note that the password of your DESY account must be changed every 6 months. For the case that your password has expired or you forgot your password, DESY provides a web form to reset here. BUT it requires two ways to prove your identity!

One of those could be your expired password.

Another one could be your email address. The password recovery tool can send you a token that you can then enter in the form. Of course this requires that you still have access to your email. Therefore it is very important that you always have the correct email address in your B2MMS record. Please check it in B2MMS.

Now how can you authenticate with a second factor if you forgot your password? To be prepared for this case, log in to the DESY password manager at, click on the three lines at the top left to open the menu, and select Self Service Settings.

Here you can enter an additional email address (for the case you loose access to your email address given in B2MMS) and your phone number to receive an SMS for the password recovery.

If you already have a one-time password app on your mobile phone, like Google Authenticator, you probably also want to generate a TOTP secret for the password recovery. If not, you may consider this an opportunity to install a TOTP app.

To summarize:

  • Make sure your email address in B2MMS is up to date.
  • Remember your password (e.g. with a password manager).
  • Set at least a phone number for an SMS token in the DESY password manager. Do it now.

KEK Registration

If you need the KEKCC, VPN, KDS accounts issued by the KEK computing center, please go back to Belle II Newcomers#KEKRegistration.

Instructions to register with the DAQ Rocket.Chat service can be found in the DAQ WebHome.

Belle VO (Virtual Organization) and DIRAC user Registration

If you want to use the Belle II Grid infrastructure, please go to Getting started on GRID (this page requires a login).

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